The Functions of the ubiquitin ligase, Skp2, and cyclin-dependent kinase 2 (Cdk2) in normal development and cancer
| Takumi Kamura | April.26-May.6.2005 | Stowers Institute for Medical Research Cold Spring Harvor Laboratory |
| HidehisaTakahashi | April.26-May.6.2005 | Stowers Institute for Medical Research Cold Spring Harvor Laboratory |
| Shuhei Kotoshiba | April.26-May.6.2005 | Stowers Institute for Medical Research Cold Spring Harvor Laboratory |
| Keiichi Nakayama | Sep. 5-11 ,2006 | LCC / NCI |
| Michiko Shirane | Sep. 6-11, 2006 | NCI |
| Masaaki Nishiyama | Sep. 6-11, 2006 | NCI |
| Ichiro Onoyama | Sep. 6-11, 2006 | NCI |
| Toru Saiga | Sep. 6-11, 2006 | NCI |
| Tadashi Nakagawa | Sep. 6-11, 2006 | NCI |
| Masatoshi Kitagawa | Sep. 6-11, 2006 | NCI |
| Ryousuke Tsunematsu | Sep. 6-11, 2006 | NCI |
Proliferation in normal cells is tightly controlled to ensure one single round of DNA replication and cell division per cell cycle. The activities of cyclin-dependent kinases [Cdks] are thought to be essential for cell cycle progression. For example, in the G1 phase there is minimal Cdk activity, in S phase Cdk activity raises to intermediate levels, and in mitosis [M phase] Cdk activity peaks at high levels. The activity of Cdks is controlled on several levels including binding of subunits [cyclins, Cdk inhibitory molecules {CKI}], phosphorylation, subcellular localization, and transcriptional control. Several Cdk regulatory proteins are short-lived and are degraded by ubiquitin mediated proteolysis. Target proteins are degraded after modification by ubiquitin chains. The recognition of target proteins is governed by ubiquitin ligase enzymes [E3]. Skp2 is one component of an E3 enzyme [SCFSkp2], which targets the CKI p27Kip1 and cyclin E. Both these proteins regulate Cdk2 that in addition binds cyclin A. Cdk2 is the most important target of p27 since overexpression of p27 leads to decreased Cdk2 activity and cell cycle arrest. In cancer, Cdk activity is elevated through mechanisms that are not known yet. Some of the best in vivo models for cancer are mouse models. We are using mouse models to study the functions of Skp2 and Cdk2 during normal development and tumorigenesis. We are proposing to generate double knockout mice that lack both Skp2 and Cdk2. In these mice, there will be no Cdk2 activity and elevated levels of p27 that can affect other targets. With these Skp2-/-Cdk2-/- mice, we are addressing a situation where p27 functions are accentuated [because of the elevated levels] and at the same time there is no Cdk2 that could bind excessive p27. Therefore, the additional p27 molecules will affect targets that could not been uncovered in a wild type background where Cdk2 is the major target of p27. Identification of new unknown targets of p27 is of great interest to understand the functions of p27 in the cell cycle and during tumorigenesis.
We have generated double knockout mice for Skp2-/-Cdk2-/- and to analyze their phenotype. First, we have analyzed the phenotype of these mice by studying different tissues by histochemistry and biochemistry. In a second stage, we have generated cell models of mouse embryonic fibroblast [MEFs], hepatocytes, thymocytes, and splenocytes. In these cells, we studied the details of cell cycle regulation including the growth characteristics, the kinetics of cell cycle transitions, the activities of Cdks, and the protein complexes formed. In a third stage, we have analyzed the induction of tumors in Skp2-/-Cdk2-/- mice by using a skin and liver tumor model. Tumors will be collected and analyzed for genetic lesions, by (immuno-) histochemistry, and by biochemistry.
Our project is of great importance not only because it will foster a close collaboration between the Nakayama and Kaldis laboratories but also because of the expected results from this study. Our model is based on a two-strike approach where two pathways [Skp2 and Cdk2] are inactivated simultaneously and the effect on normal development and tumorigenesis is studied. Pharmaceutical companies have developed molecules that inhibit the function of Cdk2 or Skp2. Here we are investigating if it would make sense to combine two different classes of drugs in cancer therapy in an animal model. The outcome of our study has great potential for future cancer therapy as well as basic research of the cell cycle.
The cyclin-dependent kinase inhibitor p27Kip1 is degraded at the G0-G1 transition of the cell cycle by the ubiquitin-proteasome pathway. Although the nuclear ubiquitin ligase (E3) SCFSkp2 is implicated in p27Kip1 degradation, proteolyis of p27Kip1 at the G0-G1 transition proceeds normally in Skp2/ cells. Moreover, p27Kip1 is exported from the nucleus to the cytoplasm at G0-G1. These data suggest the existence of a Skp2-independent pathway for the degradation of p27Kip1 at G1 phase. We now describe a previously unidentified E3 complex: KPC (Kip1 ubiquitylationpromoting complex), consisting of KPC1 and KPC2. KPC1 contains a RING-finger domain, and KPC2 contains a ubiquitin-like domain and two ubiquitin-associated domains. KPC interacts with and ubiquitylates p27Kip1 and is localized to the cytoplasm. Overexpression of KPC promoted the degradation of p27Kip1, whereas a dominant-negative mutant of KPC1 delayed p27Kip1 degradation. The nuclear export of p27Kip1 by CRM1 appears to be necessary for KPC-mediated proteolysis. Depletion of KPC1 by RNA interference also inhibited p27Kip1 degradation. KPC thus likely controls degradation of p27Kip1 in G1 phase after export of the latter from the nucleus.
September 7, 2006
| 8:00am | Pickup at the FSK Holiday Inn [I-270] | Kaldis lab |
| 8:20-9:00am | Breakfast Boardroom Bldg. 549 | |
| 9:00-9:15am | Welcoming address | Philipp Kaldis |
| 9:15-9:45am | Fbw7 is a key regulator of cell cycle exit during differentiation | Keiichi Nakayama |
| 9:45-10:00am | Characterization of mice that lack Fbw7 in bone marrow, mammary glands or liver | Ichiro Onoyama |
| 10:00-10:30am | Genetic analysis of Parc, a cullin family of E3 ubiquitin ligase | Yue Xiong |
| 10:30-10:50 | Morning Break | |
| 10:50-11:05am | Fbxo45-PAM, a novel ubiquitin ligase complex, is required for synapse formation | Toru Saiga |
| 11:05-11:20am | Rescue of loss of Cdk2 & Cdk4 | Padmakumar VC |
| 11:20-11:35am | Fbxw8 is essential for Cul1-Cul7 complex formation and for placental development | Ryosuke Tsunematsu |
| 11:35-11:50am | Functions of Rb in the absence of Cdk2 & Cdk4 | Weimin Li |
| 11:50-12:05pm | Chromatin remodeling factor CHD8 is a novel oncogene that blocks p53-mediated apoptosis pathway | Masaaki Nishiyama |
| 12:15-1:30pm | Lunch | |
| 1:30-1:45pm | DNA Damage in the absence of Cdk2 | Satya Ande |
| 1:45-2:15pm | Ubiquitin-mediated regulation of tumor suppressor proteins | Masatoshi Kitagawa |
| 2:15-2:30pm | Cdk2 & Cdk4 couple G1/S transition to mitosis | Cyril Berthet |
| 2:30-2:45pm | Potential for protein degradation and chromatin cross-talk:Characterization of the nucleolar F-box protein Fbl10 | David Frescas |
| 2:45-3:00pm | Interactions of Skp2 and Cdk2 | Shuhei Kotoshiba |
| 3:00-3:15pm | Mammalian E4 is required for cardiac development and maintenance of the nervous system | Tadashi Nakagawa |
| 3:15-3:30pm | The stability of the tumor suppressor REST/NRSF is controlled by SCF-betaTrcp-mediated degradation | Daniele Guaravaccaro |
| 3:30-4:00pm | Afternoon Break | |
| 4:00-4:15pm | Ubiquitin mediated degradation controls Claspin at different phases of the cell cycle | Florian Bassermann |
| 4:15-4:30pm | Specific roles for cyclin E1 and E2 | Kristy McDowell |
| 4:30-4:45pm | Protrudin interacts with Rab11-GDP and induces neurite formation by directional membrane trafficking | Michiko Shirane |
| 4:45-5:15pm | Control of protein translation and cell cycle checkpoints by the F-box protein ßTrcp | Michele Pagano |
| 5:15-5:45pm | Cdc2 compensates for loss of Cdk2 | Philipp Kaldis |
| 5:45-6:45pm | Round Table Discussions | |
| 6:45-7:15pm | Concluding Remarks | Keiichi Nakayama |
| 7:30pm | Dinner followed by Entertainment |
September 8, 2006
| 8:30am | Pickup at the FSK Holiday Inn | Kaldis lab |
| 9:00am | Breakfast Boardroom 549 | |
| 10:00am | Lab tour Bldg. 560 | |
| 10:45am | Discussion |
The highly ordered progression of the cell cycle is achieved by a series of elaborate mechanisms that control the periodic expression of many regulatory proteins. One such regulatory protein is the Cdk inhibitor (CKI) p27. In normal cells, the amount of p27 is high during G0 phase but rapidly decreases on the reentry of cells into G1-S. The intracellular concentration of p27 is thought to be regulated predominantly by the ubiquitin-mediated proteolytic pathway. Degradation of p27 is promoted by its phosphorylation on Thr187 by the cyclin ECdk2 complex. Skp2, an F-box protein that functions as the receptor component of an SCF ubiquitin ligase complex, binds to p27 only when Thr187 of p27 is phosphorylated; such binding then results in the ubiquitylation and degradation of p27. Skp2 also targets free cyclin E for ubiquitylation. The most obvious cellular phenotype of Skp2/ mice is the presence of markedly enlarged, polyploid nuclei and multiple centrosomes, suggestive of an impairment in the mechanism that prevents endoreplication, in which the genomic DNA content of a cell is increased without cell division. In addition to p27 and free cyclin E, several other substrates have been proposed for Skp2. We have now generated Skp2/ p27/ mice and found that they do not exhibit the overreplication phenotype, suggesting that p27 accumulation is required for its development. Hepatocytes of Skp2/ mice entered the endoduplication cycle after mitogenic stimulation, whereas this phenotype was not apparent in Skp2/ p27/ mice. Cdc2-associated kinase activity was lower in Skp2/ p27/ cells than in wild-type cells, and a reduction in Cdc2 activity was sufficient to induce nuclear enlargement and centrosome overduplication. The lack of p27 degradation in G2 phase in Skp2/ cells may thus result in suppression of Cdc2 activity and consequent inhibition of entry into M phase or reentry into S phase without passage through M phase. These data suggest that Skp2 contributes to regulation of G2-M progression by mediating the degradation of p27.
In normal cells, the amount of p27 is high during G0 phase of the cell cycle but decreases rapidly on reentry of cells into G1 phase. For example, mitogenic activation of resting lymphocytes or reexposure of serum-deprived embryonic fibroblasts to serum induces rapid degradation of p27 between 3 and 9 h after stimulation. However, Skp2 is not expressed until early S phase (18 to 24 h after stimulation), unequivocally later than the degradation of p27 apparent at G0-G1. Moreover, p27 is exported from the nucleus to the cytoplasm at G0-G1, whereas Skp2 is restricted to the nucleus. These discrepancies between the temporal and spatial patterns of p27 expression and those of Skp2 expression suggested the existence of a Skp2-independent pathway for the degradation of p27. Indeed, the down-regulation of p27 at the G0-G1 transition occurs normally in Skp2/ cells and is sensitive to proteasome inhibitors, indicating that p27 is degraded at G0-G1 by a proteasome-dependent, but Skp2-independent, mechanism. Biochemical analysis of crude extracts of Skp2/ cells revealed the presence in the cytoplasmic fraction of a Skp2-independent E3 activity that mediates the ubiquitylation of p27. This ubiquitylation of p27 is not dependent on the phosphorylation of threonine-187, which is a prerequisite for Skp2-mediated ubiquitylation. We have recently purified an E3 enzyme, designated KPC (Kip1 ubiquitylation-promoting complex), that interacts with and ubiquitylates p27 in G1 phase and is localized to the cytoplasm of mammalian cells.
We also carried out a comprehensive characterization of ubiquitin-conjugated and ubiquitin-associated proteins in mammalian cells. The proteins were purified by immunoaffinity chromatography under denaturing or native conditions. They were then digested with trypsin, and the resulting peptides were analyzed by two-dimensional liquid chromatography and tandem mass spectrometry. A total of 670 distinct proteins was identified; 345 proteins (51%) were classified as Urp-D (ubiquitin-related proteome under the denaturing condition) and comprised ubiquitin-conjugated molecules, whereas 325 proteins (49%) were classified as Urp-N (ubiquitin-related proteome only under the native condition) and included molecules that associated with ubiquitylated proteins. The proportions of proteins in various functional categories differed substantially between Urp-D and Urp-N. Many ribosomal subunits were detected in the Urp-D group of proteins and several of these subunits were directly shown to be ubiquitylated by mass spectrometric analysis, suggesting that ubiquitylation might play an important role in the regulation and/or quality control of ribosomal proteins. Our results demonstrate the potential of proteomics analysis of protein ubiquitylation to provide important insight into the regulation of protein stability and other ubiquitin-related cellular functions.
We also studied an F-box protein Fbw7, which is structurally similar to Skp2. Cell proliferation is tightly controlled during differentiation. In T cell development, the cell cycle is normally arrested at the CD4+CD8+ stage, but the mechanism underlying such differentiation-specific exit from the cell cycle has been unclear. Fbw7, an F-box protein subunit of an SCF-type ubiquitin ligase complex, induces the degradation of positive regulators of the cell cycle, such as c-Myc, c-Jun, cyclin E and Notch. FBW7 is often mutated in a subset of human cancers. We have now achieved conditional inactivation of the Fbw7 gene in the T cell lineage of mice and found that the cell cycle is not arrested at the CD4+CD8+ stage in the homozygous mutant animals. The mutant mice manifested thymic hyperplasia likely through c-Myc accumulation and eventually developed thymic lymphoma. In contrast, mature T cells of the mutant mice failed to proliferate in response to mitogenic stimulation and underwent apoptosis in association with accumulation of c-Myc and p53. These abnormalities were corrected by deletion of p53. Our results suggest that Fbw7 regulates the cell cycle in a differentiation-dependent manner, its loss resulting in c-Myc accumulation that leads to hyperproliferation in immature T cells but to p53-dependent cell cycle arrest and apoptosis in mature T cells.
Rodier, G., Makris, C., Coulombe, P., Scime, A., Nakayama, K., Nakayama, K.I., Meloche, S.: p107 inhibits G1 to S phase progression by down-regulating expression of the F-box protein Skp2. J. Cell Biol., 168: 55-66 (2005).
Kotake, Y., Nakayama, K., Ishida, N., Nakayama, K.I.: Role of serine 10 phosphorylation in p27 stabilization revealed by analysis of p27 knock-in mice harboring a serine 10 mutation. J. Biol. Chem., 280: 1095-1102 (2005).
Harada, K., Takeuchi, H., Oike, M., Matsuda, M., Kanematsu, T., Yagisawa, H., Nakayama, K.I., Maeda, K., Erneux, C., Hirata, M.: Role of PRIP-1, a novel Ins(1,4,5)P(3) binding protein, in Ins(1,4,5)P(3)-mediated Ca(2+) signaling. J. Cell. Physiol., 202: 422-433 (2005).
Uchida, T., Nakamura, T., Hashimoto, N., Matsuda, T., Kotani, K., Sakaue, H., Kido, Y., Hayashi, Y., Nakayama, K.I., White, M. F., Kasuga, M.: Deletion of Cdkn1b ameliorates hyperglycemia by maintaining compensatory hyperinsulinemia in diabetic mice. Nature Med., 11: 175-182 (2005).
Takahashi, H., Hatakeyama, S., Saitoh, H., Nakayama, K.I.: Noncovalent SUMO-1 binding activity of thymine DNA glycosylase (TDG) is required for its SUMO-1 modification and colocalization with the promyelocytic leukemia protein. J. Biol. Chem., 280: 5611-5621 (2005).
He, C. H., Waxman, A. B., Lee, C. G., Link, H., Rabach, M. E., Ma, B., Chen, Q., Zhu, Z., Zhong, M., Nakayama, K., Nakayama, K.I., Homer, R., Elias, J. A.: Bcl-2-related protein A1 is an endogenous and cytokine-stimulated mediator of cytoprotection in hyperoxic acute lung injury. J. Clin. Invest., 115: 1039-1048 (2005).
Jackson, D., Zheng, Y., Lyo, D., Shen, Y., Nakayama, K., Nakayama, K.I., Humphries, M. J., Reyland, M. E., Foster, D. A.: Suppression of cell migration by protein kinase Cdelta. Oncogene, 24: 3067-3072 (2005).
Kotoshiba, S., Kamura, T., Hara, T., Ishida, N., Nakayama, K.I.: Molecular dissection of the interaction between p27 and Kip1 ubiquitylation-promoting complex, the ubiquitin ligase that regulates proteolysis of p27 in G1 phase. J. Biol. Chem., 280: 17694-17700 (2005).
Kase, S., Yoshida, K., Ikeda, H., Harada, T., Harada, C., Imaki, J., Ohgami, K., Shiratori, K., Nakayama, K.I., Nakayama, K., Ohno, S.: Disappearance of p27(KIP1) and increase in proliferation of the lens cells after extraction of most of the fiber cells of the lens. Curr. Eye Res., 30: 437-442 (2005).
Jiang, H., Chang, F. C., Ross, A. E., Lee, J., Nakayama, K.I., Nakayama, K., Desiderio, S.: Ubiquitylation of RAG-2 by Skp2-SCF links destruction of the V(D)J recombinase to the cell cycle. Mol. Cell, 18: 699-709 (2005).
Pushkarsky, T., Yurchenko, V., Vanpouille, C., Brichacek, B., Vaisman, I., Hatakeyama, S., Nakayama, K.I., Sherry, B., Bukrinsky, M. I.: Cell surface expression of CD147/EMMPRIN is regulated by cyclophilin 60. J. Biol. Chem., 280: 27866-27871 (2005).
Wang, H. Q., Nakaya, Y., Du, Z., Yamane, T., Shirane, M., Kudo, T., Takeda, M., Takebayashi, K., Noda, Y., Nakayama, K.I., Nishimura, M.: Interaction of presenilins with FKBP38 promotes apoptosis by reducing mitochondrial Bcl-2. Hum. Mol. Genet., 14: 1889-1902 (2005).
Kase, S., Yoshida, K., Nakayama, K.I., Nakayama, K., Ikeda, H., Harada, T., Harada, C., Ohgami, K., Shiratori, K., Ohno, S.: Phosphorylation of p27(KIP1) in the developing retina and retinoblastoma. Int. J. Mol. Med., 16: 257-262 (2005).
Chen, Z., Foster, M. W., Zhang, J., Mao, L., Rockman, H. A., Kawamoto, T., Kitagawa, K., Nakayama, K.I., Hess, D. T., Stamler, J. S.: An essential role for mitochondrial aldehyde dehydrogenase in nitroglycerin bioactivation. Proc. Natl. Acad. Sci. U. S. A., 102: 12159-12164 (2005).
Hatakeyama, S., Watanabe, M., Fujii, Y., Nakayama, K.I.: Targeted destruction of c-Myc by an engineered ubiquitin ligase suppresses cell transformation and tumor formation. Cancer Res., 65: 7874-7879 (2005).
Hino, S., Tanji, C., Nakayama, K.I., Kikuchi, A.: Phosphorylation of beta-catenin by cyclic AMP-dependent protein kinase stabilizes beta-catenin through inhibition of its ubiquitination. Mol. Cell. Biol., 25: 9063-9072 (2005).
Hara, T., Kamura, T., Kotoshiba, S., Takahashi, H., Fujiwara, K., Onoyama, I., Shirakawa, M., Mizushima, N., Nakayama, K.I.: Role of the UBL-UBA protein KPC2 in degradation of p27 at G1 phase of the cell cycle. Mol. Cell. Biol., 25: 9292-9303 (2005).
Matsumoto, M., Hatakeyama, S., Oyamada, K., Oda, Y., Nishimura, T., Nakayama, K.I.: Large-scale analysis of the human ubiquitin-related proteome. Proteomics, 5: 4145-4151 (2005).
Kaneko-Oshikawa, C., Nakagawa, T., Yamada, M., Yoshikawa, H., Matsumoto, M., Yada, M., Hatakeyama, S., Nakayama, K., Nakayama, K.I.: Mammalian E4 is required for cardiac development and maintenance of the nervous system. Mol. Cell. Biol., 25: 10953-10964 (2005).
Yogosawa, S., Hatakeyama, S., Nakayama, K.I., Miyoshi, H., Kohsaka, S., Akazawa, C.: Ubiquitylation and degradation of serum-inducible kinase by hVPS18, a RING-H2 type ubiquitin ligase. J. Biol. Chem., 280: 41619-41627 (2005).
Nishitani, H., Sugimoto, N., Roukos, V., Nakanishi, Y., Saijo, M., Obuse, C., Tsurimoto, T., Nakayama, K.I., Nakayama, K., Fujita, M., Lygerou, Z., Nishimoto, T.: Two E3 ubiquitin ligases, SCF-Skp2 and DDB1-Cul4, target human Cdt1 for proteolysis. EMBO J., 25: 1126-1136 (2006).
Kase, S., Yoshida, K., Ohgami, K., Shiratori, K., Suzuki, Y., Nakayama, K.I., Ohno, S.: Expression of cdc2 and p27(KIP1) phosphorylation in mitotic cells of the human retinoblastoma. Int. J. Mol. Med., 17: 465-468 (2006).
Iwanaga, R., Komori, H., Ishida, S., Okamura, N., Nakayama, K., Nakayama, K.I., Ohtani, K.: Identification of novel E2F1 target genes regulated in cell cycle-dependent and independent manners. Oncogene, 25: 1786-1798 (2006).
Kase, S., Yoshida, K., Harada, T., Harada, C., Namekata, K., Suzuki, Y., Ohgami, K., Shiratori, K., Nakayama, K.I., Ohno, S.: Phosphorylation of extracellular signal-regulated kinase and p27(KIP1) after retinal detachment. Graefes Arch. Clin. Exp. Ophthalmol., 244: 352-358 (2006).
Sugihara, E., Kanai, M., Saito, S., Nitta, T., Toyoshima, H., Nakayama, K., Nakayama, K.I., Fukasawa, K., Schwab, M., Saya, H., Miwa, M.: Suppression of centrosome amplification after DNA damage depends on p27 accumulation. Cancer Res., 66: 4020-4029 (2006).
Ryer, E. J., Hom, R. P., Sakakibara, K., Nakayama, K.I., Nakayama, K., Faries, P. L., Liu, B., Kent, K. C.: PKCdelta is necessary for Smad3 expression and transforming growth factor beta-induced fibronectin synthesis in vascular smooth muscle cells. Arterioscler. Thromb. Vasc. Biol., 26: 780-786 (2006).
Humphries, M. J., Limesand, K. H., Schneider, J. C., Nakayama, K.I., Anderson, S. M., Reyland, M. E.: Suppression of apoptosis in the protein kinase Cdelta null mouse in vivo. J. Biol. Chem., 281: 9728-9737 (2006).
Kase, S., Yoshida, K., Ohgami, K., Shiratori, K., Ohno, S., Nakayama, K.I.: Phosphorylation of p27(KIP1) in the mitotic cells of the corneal epithelium. Curr. Eye Res., 31: 307-312 (2006).
Parcellier, A., Brunet, M., Schmitt, E., Col, E., Didelot, C., Hammann, A., Nakayama, K., Nakayama, K.I., Khochbin, S., Solary, E., Garrido, C.: HSP27 favors ubiquitination and proteasomal degradation of p27Kip1 and helps S-phase re-entry in stressed cells. FASEB J., (2006).
Fotovati, A., Nakayama, K., Nakayama, K.I.: Impaired germ cell development due to compromised cell cycle progression in Skp2-deficient mice. Cell Div., 1: 4 (2006).
Yoshida, K., Yamaguchi, T., Shinagawa, H., Taira, N., Nakayama, K.I., Miki, Y.: Protein kinase C {delta} activates topoisomerase II{alpha} to induce apoptotic cell death in response to DNA damage. Mol. Cell. Biol., 26: 3414-3431 (2006).
Niki, S., Oshikawa, K., Mouri, Y., Hirota, F., Matsushima, A., Yano, M., Han, H., Bando, Y., Izumi, K., Matsumoto, M., Nakayama, K.I., Kuroda, N., Matsumoto, M.: Alteration of intra-pancreatic target-organ specificity by abrogation of Aire in NOD mice. J. Clin. Invest., 116: 1292-1301 (2006).
Shukla, A., Barrett, T. F., Nakayama, K.I., Nakayama, K., Mossman, B. T., Lounsbury, K. M.: Transcriptional up-regulation of MMP12 and MMP13 by asbestos occurs via a PKCdelta-dependent pathway in murine lung. FASEB J., 20: 997-999 (2006).
Nojima, T., Hayashi, K., Goitsuka, R., Nakayama, K., Nakayama, K.I., Kitamura, D.: Double knockout mice show BASH and PKCdelta have different epistatic relationships in B cell maturation and CD40-mediated activation. Immunol. Lett., 105: 48-54 (2006).
Shimazu, T., Komatsu, Y., Nakayama, K.I., Fukazawa, H., Horinouchi, S., Yoshida, M.: Regulation of SV40 large T-antigen stability by reversible acetylation. Oncogene, (2006).
Tsukuba, T., Yamamoto, S., Yanagawa, M., Okamoto, K., Okamoto, Y., Nakayama, K.I., Kadowaki, T., Yamamoto, K.: Cathepsin E-deficient mice show increased susceptibility to bacterial infection associated with the decreased expression of multiple cell surface Toll-like receptors. J. Biochem., 140: 57-66 (2006).
Tsunematsu, R., Nishiyama, M., Kotoshiba, S., Saiga, T., Kamura, T., Nakayama, K.I.: Fbxw8 is essential for Cul1-Cul7 complex formation and for placental development. Mol. Cell. Biol., 26: 6157-6169 (2006).
Fujii, Y., Yada, M., Nishiyama, M., Kamura, T., Takahashi, H., Tsunematsu, R., Susaki, E., Nakagawa, T., Matsumoto, A., Nakayama, K.I.: Fbxw7 contributes to tumor suppression by targeting multiple proteins for ubiquitin-dependent degradation. Cancer Sci., 97: 729-736 (2006).
Kanematsu, T., Yasunaga, A., Mizoguchi, Y., Kuratani, A., Kittler, J. T., Jovanovic, J. N., Takenaka, K., Nakayama, K.I., Fukami, K., Takenawa, T., Moss, S. J., Nabekura, J., Hirata, M.: Modulation of GABA(A) receptor phosphorylation and membrane trafficking by phospholipase C-related inactive protein/protein phosphatase 1 and 2A signaling complex underlying brain-derived neurotrophic factor-dependent regulation of GABAergic inhibition. J. Biol. Chem., 281: 22180-22189 (2006).
Hiramatsu, Y., Kitagawa, K., Suzuki, T., Uchida, C., Hattori, T., Kikuchi, H., Oda, T., Hatakeyama, S., Nakayama, K.I., Yamamoto, T., Konno, H., Kitagawa, M.: Degradation of Tob1 mediated by SCFSkp2-dependent ubiquitination. Cancer Res., 66: 8477-8483 (2006).
Matsumoto, A., Onoyama, I., Nakayama, K.I.: Expression of mouse Fbxw7 isoforms is regulated in a cell cycle- or p53-dependent manner. Biochem. Biophys. Res. Commun., 350: 114-119 (2006).
Shirane, M., Nakayama, K.I.: Protrudin induces neurite formation by directional membrane trafficking. Science, 314: 818-821 (2006).
Hara, K., Nakayama, K.I., Nakayama, K.: Geminin is essential for the development of preimplantation mouse embryos. Genes Cells, 11: 1281-1293 (2006).
Takahashi, A., Ohtani, N., Yamakoshi, K., Iida, S., Tahara, H., Nakayama, K., Nakayama, K.I., Ide, T., Saya, H., Hara, E.: Mitogenic signalling and the p16INK4a-Rb pathway cooperate to enforce irreversible cellular senescence. Nature Cell Biol., 8: 1291-1297 (2006).
Gao, Y., Kitagawa, K., Hiramatsu, Y., Kikuchi, H., Isobe, T., Shimada, M., Uchida, C., Hattori, T., Oda, T., Nakayama, K., Nakayama, K.I., Tanaka, T., Konno, H., Kitagawa, M.: Up-regulation of GPR48 induced by down-regulation of p27Kip1 enhances carcinoma cell invasiveness and metastasis. Cancer Res., 66: 11623-11631 (2006).
Pula, G., Schuh, K., Nakayama, K., Nakayama, K.I., Walter, U., Poole, A. W.: PKCdelta regulates collagen-induced platelet aggregation through inhibition of VASP-mediated filopodia formation. Blood, 108: 4035-4044 (2006).
Shukla, A., Lounsbury, K. M., Barrett, T. F., Gell, J., Rincon, M., Butnor, K. J., Taatjes, D. J., Davis, G. S., Vacek, P., Nakayama, K.I., Nakayama, K., Steele, C., Mossman, B. T.: Asbestos-induced peribronchiolar cell proliferation and cytokine production are attenuated in lungs of protein kinase C-{delta} knockout mice. Am. J. Pathol., 170: 140-151 (2007).
Tu, X., Joeng, K. S., Nakayama, K.I., Nakayama, K., Rajagopal, J., Carroll, T. J., McMahon, A. P., Long, F.: Noncanonical Wnt signaling through G protein-linked PKCdelta activation promotes bone formation. Dev. Cell, 12: 113-127 (2007).
Yanagawa, M., Tsukuba, T., Nishioku, T., Okamoto, Y., Okamoto, K., Takii, R., Terada, Y., Nakayama, K.I., Kadowaki, T., Yamamoto, K.: Cathepsin E deficiency induces a novel form of lysosomal storage disorder showing the accumulation of lysosomal membrane sialoglycoproteins and the elevation of lysosomal pH in macrophages. J. Biol. Chem., 282: 1851-1862 (2007).
Itoh, Y., Masuyama, N., Nakayama, K., Nakayama, K.I., Gotoh, Y.: The cyclin-dependent kinase inhibitors p57 and p27 regulate neuronal migration in the developing mouse neocortex. J. Biol. Chem., 282: 390-396 (2007).
Sakai, T., Sakaue, H., Nakamura, T., Okada, M., Matsuki, Y., Watanabe, E., Hiramatsu, R., Nakayama, K., Nakayama, K.I., Kasuga, M.: Skp2 controls adipocyte proliferation during the development of obesity. J. Biol. Chem., 282: 2038-2046 (2007).
Uchida, T., Iwashita, N., Ohara-Imaizumi, M., Ogihara, T., Nagai, S., Choi, J. B., Tamura, Y., Tada, N., Kawamori, R., Nakayama, K.I., Nagamatsu, S., Watada, H.: Protein kinase Cdelta plays a non-redundant role in insulin secretion in pancreatic beta cells. J. Biol. Chem., 282: 2707-2716 (2007).
Mizokami, A., Kanematsu, T., Ishibashi, H., Yamaguchi, T., Tanida, I., Takenaka, K., Nakayama, K.I., Fukami, K., Takenawa, T., Kominami, E., Moss, S. J., Yamamoto, T., Nabekura, J., Hirata, M.: Phospholipase C-related inactive protein is involved in trafficking of gamma2 subunit-containing GABA(A) receptors to the cell surface. J. Neurosci., 27: 1692-1701 (2007).
Matsuda, T., Matsumoto, A., Uchida, M., Kanaly, R., Misaki, K., Shibutani, S., Kawamoto, T., Kitagawa, K., Nakayama, K.I., Tomokuni, K., Ichiba, M.: Increased formation of hepatic N2-ethylidene-2'-deoxyguanosine DNA adducts in aldehyde dehydrogenase 2 knockout mice treated with ethanol. Carcinogenesis, (2007).
Liu, Z., Liu, X., Nakayama, K.I., Nakayama, K., Ye, K.: Protein kinase C-delta phosphorylates Ebp1 and prevents its proteolytic degradation, enhancing cell survival. J. Neurochem., 100: 1278-1288 (2007).
Moller, C., Karlberg, M., Abrink, M., Nakayama, K.I., Motoyama, N., Nilsson, G.: Bcl-2 and Bcl-XL are indispensable for the late phase of mast cell development from mouse embryonic stem cells. Exp. Hematol., 35: 385-393 (2007).
Nakagawa, T., Shirane, M., Iemura, S., Natsume, T., Nakayama, K.I.: Anchoring of the 26S proteasome to the organellar membrane by FKBP38. Genes Cells, in press.
Miyamoto, K., Araki, K.Y., Naka, K., Arai, F., Takubo, K., Yamazaki, S., Matsuoka, S., Miyamoto, T., Ito, K., Ohmura, M., Chen, C., Hosokawa, K., Nakauchi, H., Nakayama, K., Nakayama, K.I., Harada, M., Motoyama, N., Suda, T., Hirao, A. Foxo3a is essential for maintenance of the hematopoietic stem cell pool. Cell Stem Cell, in press.
Susaki, E., Nakayama, K., Nakayama, K.I.: Cyclin D2 translocates p27 out of the nucleus and promotes its degradation at the G0-G1 transition. Mol. Cell. Biol., in press.