Multiple tasks of Glycogen synthase kinase-3beta (GSK-3Î² ) and its partners.
Degree: PhD, Biological Sciences, 2007, NSYSU
Glycogen synthase kinase-3 (GSK-3) is a serine/threonine protein kinase which plays a key role in several signaling pathways and its homologues have been identified in most eukaryotes. Since GSK3Î²is an essential protein kinase that regulates numerous functions within the cell, an effort to survey possible GSK3Î²- interacting proteins from a human testis cDNA library using the yeast two-hybrid system is made. Two interesting candidates are chosen to characterize their functions in this study. One is a centrosomal protein, hNinein, and the other is a novel inhibitor of GSK3Î², designated as GSKIP (GSK3Î² interaction protein).
In the first part of the present thesis we describe the identification of four diverse CCII-termini of human hNinein isoforms, including a novel isoform 6, by differential expression in a tissue-specific manner. In a kinase assay, the CCII region of hNinein isoforms provides a differential phosphorylation site by GSK3Î². In addition, either N-terminal or CCIIZ domain disruption may cause hNinein conformational change which recruits Î³-tubulin to centrosomal or non-centrosomal hNinein-containing sites. Further, depletion of all hNinein isoforms caused a significant decrease in the Î³-tubulin signal in the centrosome. In domain swapping, it clearly shows that the CCIIX-CCIIY region provides docking sites for Î³-tubulin. Moreover, nucleation of microtubules from the centrosome is significantly affected by the overexpression of either the full-length hNinein or CCIIX-CCIIY region. Taken together, these results show that the centrosomal targeting signals of hNinein have a role not only in regulating hNinein conformation, resulting in localization change, but also provide docking sites to recruit Î³-tubulin at centrosomal and non-centrosomal sites.
In the second part of the thesis we describe another candidate, GSK3Î²interaction protein (GSKIP), to characterize its functions in neuron differentiation. We use human neuroblastoma SH-SY5Y cells as a model of neuronal cell differentiation. When overexpression of GSKIP prevents neurite outgrowth from RA-mediated differentiation, this result is similar to the presence of LiCl or SB415286, an inhibitor of GSK3Î². Further, GSKIP regulates the activity of GSK3Î² through protein-protein interactions rather than post-modulation and GSKIP may affect GSK3Î² on neurite outgrowth via inhibiting the specific phosphorylation site of tau. In addition to inhibition of neurite outgrowth, GSKIP overexpressed in SH-SY5Y cells also promotes cell cycle progression by analyzing cell proliferation with cell growth and MTT assay. Furthermore, GSKIP raises the level of Î²-catenin and cyclin D1 through inhibition of GSK3Î² activity in RA-mediated differentiation SH-SY5Y cells. Taken together, the data suggest that GSKIP, a dual functional molecule, is able to inhibit neurite outgrowth and promote cell proliferation via negative regulation of GSK3Î² activity in RA-mediated differentiation of SH-SY5Y cells.
Advisors/Committee Members: Chung-Lung Cho (chair), Yi-Ren Hong (committee member), Pei-Jung Lu (chair), Wen-Tsan Chang (chair), Ching-Mei Hsu (committee member), Bei-Chang Yang (chair), De-Ching Chang (chair).
Subjects/Keywords: neurite; Glycogen synthase kinase-3; neuroblastoma; centrosomal protein; GSKIP; gamma-tubulin docking sites
to Zotero / EndNote / Reference
APA (6th Edition):
Lin, C. (2007). Multiple tasks of Glycogen synthase kinase-3beta (GSK-3Î² ) and its partners. (Doctoral Dissertation). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0910107-105059
Chicago Manual of Style (16th Edition):
Lin, Ching-chih. “Multiple tasks of Glycogen synthase kinase-3beta (GSK-3Î² ) and its partners.” 2007. Doctoral Dissertation, NSYSU. Accessed May 12, 2021.
MLA Handbook (7th Edition):
Lin, Ching-chih. “Multiple tasks of Glycogen synthase kinase-3beta (GSK-3Î² ) and its partners.” 2007. Web. 12 May 2021.
Lin C. Multiple tasks of Glycogen synthase kinase-3beta (GSK-3Î² ) and its partners. [Internet] [Doctoral dissertation]. NSYSU; 2007. [cited 2021 May 12].
Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0910107-105059.
Council of Science Editors:
Lin C. Multiple tasks of Glycogen synthase kinase-3beta (GSK-3Î² ) and its partners. [Doctoral Dissertation]. NSYSU; 2007. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0910107-105059