In addition to the well-known protein kinase CDC2, a novel protein kinase, NIMA, plays an essential role in regulating mitosis in the lower eukaryotic Aspergillus nidulans. I previously demonstrated that a putative NIMA-like pathway also is required for entry into mitosis in human cells. Recently, I isolated three human genes, PIN1-3, encoding proteins that physically interact with NIMA and functionally suppress its function. Characterization of PIN1 and PIN3 has demonstrated that they encode important mitotic regulators, further providing strong support for the existence of a NIMA-like pathway in human cells. This proposal will focus on determining the function and regulation of Pin2. Preliminary results show that Pin2 is specifically associated with a putative protein kinase, Pink1, which is a strong candidate for the human NIMA functional homologue. Interestingly, Pin2 is also specifically interacts with double- stranded repeat DNA located in human telomeres. Telomeres, DNA- protein complexes capping chromosome ends, are essential for maintaining the genomic stability and the proliferative capacity of the cell. Furthermore, deregulation of telomere length has been shown to be implicated in cancer and aging. Although these results suggest a link between telomere length and growth control, little is known about the regulatory molecules and mechanisms involved. Our findings that the major telomeric DNA-binding protein Pin2 interacts with the Aspergillus mitotic kinase NIMA suggests that Pin2 and the putative human NIMA homologue Pink1 may be key molecules connecting the cell cycle and telomere function. To test this hypothesis, we first plan to determine the role of Pin2 in the cell cycle by examining the cell cycle-specific expression and localization of Pin2 and determining the effects of upregulating and downregulating the Pin2 function on cell cycle progression and the putative NIMH mitotic pathway. Next, we will determine the role of Pin2 in regulating telomere length by determining the relationship between the Pin2 concentration and telomere length during senescence, examining the effects of altering the Pin2 function on telomere length and cellular senescence, and elucidating the role of Pin2 in regulating telomerase activity. Finally, we will study the regulation of Pin2 by determining Pin2 phosphorylation sites and their functions, as well as purifying and cloning the Pin2-associated kinase Pink1. Once the Pink1 cDNA is isolated, we will determine whether it is indeed the human NIMA homologue and how it regulates Pin2 and the cell cycle. These studies should help elucidate the role and molecular mechanisms of the mammalian NIMA-like pathway in regulation of mitosis and telomere homeostasis, and may have novel implications for understanding mechanisms of aging and carcinogenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM056230-03
Application #
6019315
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1997-08-01
Project End
2002-07-31
Budget Start
1999-08-01
Budget End
2000-07-31
Support Year
3
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Beth Israel Deaconess Medical Center
Department
Type
DUNS #
076593722
City
Boston
State
MA
Country
United States
Zip Code
02215
Rajbhandari, Prashant; Finn, Greg; Solodin, Natalia M et al. (2012) Regulation of estrogen receptor * N-terminus conformation and function by peptidyl prolyl isomerase Pin1. Mol Cell Biol 32:445-57
Lee, Tae Ho; Chen, Chun-Hau; Suizu, Futoshi et al. (2011) Death-associated protein kinase 1 phosphorylates Pin1 and inhibits its prolyl isomerase activity and cellular function. Mol Cell 42:147-59
Balastik, Martin; Lim, Jormay; Pastorino, Lucia et al. (2007) Pin1 in Alzheimer's disease: multiple substrates, one regulatory mechanism? Biochim Biophys Acta 1772:422-9
Lee, Tae Ho; Perrem, Kilian; Harper, J Wade et al. (2006) The F-box protein FBX4 targets PIN2/TRF1 for ubiquitin-mediated degradation and regulates telomere maintenance. J Biol Chem 281:759-68
Lu, Kun Ping; Suizu, Futoshi; Zhou, Xiao Zhen et al. (2006) Targeting carcinogenesis: a role for the prolyl isomerase Pin1? Mol Carcinog 45:397-402
Wulf, Gerburg; Finn, Greg; Suizu, Futoshi et al. (2005) Phosphorylation-specific prolyl isomerization: is there an underlying theme? Nat Cell Biol 7:435-41
Lim, Jormay; Lu, Kun Ping (2005) Pinning down phosphorylated tau and tauopathies. Biochim Biophys Acta 1739:311-22
Wulf, Gerburg; Garg, Priti; Liou, Yih-Cherng et al. (2004) Modeling breast cancer in vivo and ex vivo reveals an essential role of Pin1 in tumorigenesis. EMBO J 23:3397-407
Lu, Kun Ping (2004) Pinning down cell signaling, cancer and Alzheimer's disease. Trends Biochem Sci 29:200-9
Lu, Kun Ping; Liou, Yih-Cherng; Vincent, Inez (2003) Proline-directed phosphorylation and isomerization in mitotic regulation and in Alzheimer's Disease. Bioessays 25:174-81

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