Role of NEK1 in VHL and Cell Cycle Regulation

Hdl Handle:
http://hdl.handle.net/10675.2/556483
Title:
Role of NEK1 in VHL and Cell Cycle Regulation
Authors:
Patil, Mallikarjun
Abstract:
Nekl is the member of NIMA (Never in mitosis gene A) related protein kinase family that is widely expressed in mammals. Nekl is an essential protein because loss of function in Nekl gene causes polycystic kidney disease in mice, which is similar to ADPKD (Autosomal Dominant Polycystic Kidney Disease) in humans. In Humans Nekl mutations also cause short rib polydactyl syndrome characterized by renal cysts and other developmental defects. At the cellular level Nekl thought to regulate ciliogenesis, centrosome duplication and DNA damage response.Nekl mutations leading to PKD have long been attributed to its role in ciliogenesis. Interestingly, VHL (Von hippel lindau) protein a known tumor suppressor is also involved in ciliogenesis.VHL mutations cause cystic kidney disease and renal clear cell carcinoma. Since Nekl and VHL are involved in ciliogenesis and cystic kidney disease, my overall goal was to investigate if Nekl and VHL are part of common regulatory pathway and also to investigate the role of Nekl in cell cycle regulation. My results indicate that Nekl phosphorylates VHL and this has important role in cilia regulation. Nekl phosphorylates VHL on multiple sites and S168 of VHL a site phosphorylated by Nekl significantly affects its stability. Importantly renal cells expressing S168A VHL that cannot be phosphorylated by Nekl grow cilia that are resistant to serum stimulation and Nocodazole treatment. Surprisingly I also found that Nekl is an essential regulator of S phase. Nekl knockdown in HEK cells blocks cell cycle progression. Further characterization Nekl showed that Nekl is needed for S phase progression and DNA replication. Nekl deficient cells have replication stress and activate cell cycle check point. Nekl loads on to chromatin and this increases during replication stress. We have also identified that Nekl interacts with and affects Ku80 loading on to chromatin. These findings have provided novel insights into the Nekl functions, which help in understanding the pathophysiology and development of polycystic kidney disease in mice and short rib polydactyl syndrome mejawski in humans.
Affiliation:
Department of Cellular Biology and Anatomy
Issue Date:
2013
URI:
http://hdl.handle.net/10675.2/556483
Additional Links:
http://ezproxy.augusta.edu/login?url=http://search.proquest.com/docview/1448690931?accountid=12365
Type:
Dissertation
Appears in Collections:
Theses and Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.authorPatil, Mallikarjunen
dc.date.accessioned2015-06-05T18:30:15Zen
dc.date.available2015-06-05T18:30:15Zen
dc.date.issued2013en
dc.identifier.urihttp://hdl.handle.net/10675.2/556483-
dc.description.abstractNekl is the member of NIMA (Never in mitosis gene A) related protein kinase family that is widely expressed in mammals. Nekl is an essential protein because loss of function in Nekl gene causes polycystic kidney disease in mice, which is similar to ADPKD (Autosomal Dominant Polycystic Kidney Disease) in humans. In Humans Nekl mutations also cause short rib polydactyl syndrome characterized by renal cysts and other developmental defects. At the cellular level Nekl thought to regulate ciliogenesis, centrosome duplication and DNA damage response.Nekl mutations leading to PKD have long been attributed to its role in ciliogenesis. Interestingly, VHL (Von hippel lindau) protein a known tumor suppressor is also involved in ciliogenesis.VHL mutations cause cystic kidney disease and renal clear cell carcinoma. Since Nekl and VHL are involved in ciliogenesis and cystic kidney disease, my overall goal was to investigate if Nekl and VHL are part of common regulatory pathway and also to investigate the role of Nekl in cell cycle regulation. My results indicate that Nekl phosphorylates VHL and this has important role in cilia regulation. Nekl phosphorylates VHL on multiple sites and S168 of VHL a site phosphorylated by Nekl significantly affects its stability. Importantly renal cells expressing S168A VHL that cannot be phosphorylated by Nekl grow cilia that are resistant to serum stimulation and Nocodazole treatment. Surprisingly I also found that Nekl is an essential regulator of S phase. Nekl knockdown in HEK cells blocks cell cycle progression. Further characterization Nekl showed that Nekl is needed for S phase progression and DNA replication. Nekl deficient cells have replication stress and activate cell cycle check point. Nekl loads on to chromatin and this increases during replication stress. We have also identified that Nekl interacts with and affects Ku80 loading on to chromatin. These findings have provided novel insights into the Nekl functions, which help in understanding the pathophysiology and development of polycystic kidney disease in mice and short rib polydactyl syndrome mejawski in humans.en
dc.relation.urlhttp://ezproxy.augusta.edu/login?url=http://search.proquest.com/docview/1448690931?accountid=12365en
dc.rightsCopyright protected. Unauthorized reproduction or use beyond the exceptions granted by the Fair Use clause of U.S. Copyright law may violate federal law.en
dc.subjectNIMA related kinase1 (Nek1)en
dc.subjectPolycystic kidney diseaseen
dc.subjectVon-Hippel landau protein (PVHL)en
dc.subjectCell cycleen
dc.subjectCiliaen
dc.subjectHuman embryonic kidney cellsen
dc.subjectDNA replicationen
dc.titleRole of NEK1 in VHL and Cell Cycle Regulationen
dc.typeDissertationen
dc.contributor.departmentDepartment of Cellular Biology and Anatomyen
dc.description.advisorDong, Zhengen
dc.description.committeeNot Listeden
dc.description.degreeDoctor of Philosophy (Ph.D.)en
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