The functional roles of O-GlcNAcylation on Sam68 protein
| Autor: | Shu-Ying Wang, 王淑穎 |
|---|---|
| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 O-GlcNAcylation is a dynamic, reversible and inducible post-translational modification which is the addition of a single -N-acetylglucosamine to serine/threonine residues of nuclear or cytosolic proteins. O-GlcNAcylation is involved in many crucial biological processes, such as signal transduction, transcription, cell cycle regulation, and metabolism. Dysregulation of O-GlcNAcylation has been shown to participate in the pathological progression of many human diseases including cancer. Previously, we found that Sam68 is O-GlcNAcylated and this modification level associates with tumor invasiveness in lung adenocarcinoma cell lines. Therefore, we are interested in exploring the functional consequences of O-GlcNAc modification on Sam68. First, we found that Sam68 protein associates with O-GlcNAc transferase in the nucleus. By generating serial deletion mutants of Sam68, we discovered that the N-terminal domain (residues 1 to 56) is required for its O-GlcNAcylation. Then we mutated serine and threonine residues to alanine and compared the O-GlcNAcylation levels by succinylated wheat germ agglutinin (sWGA) pull-down assay and immunoprecipitation. The results showed that, compared to wild-type, Sam68 mutants (6A, 5A and 11A) can only be slightly pulled down by sWGA with reduced O-GlcNAc signal, suggesting that multiple serines/threonines in N-terminal of Sam68 are important for its O-GlcNAcylation. Moreover, we found that Sam68 regulates cell migration and proliferation in lung adenocarcinoma cells. Compared to wild-type, Sam68 mutants (6A, 5A and 11A) had no difference in cell proliferation, but Sam68 mutant 6A might involve in cell migration. We will further investigate the molecular mechanisms of O-GlcNAcylated Sam68 in regulating tumor progression. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|