OSBP-related protein 8 (ORP8) interacts with Homo sapiens sperm associated antigen 5 (SPAG5) and mediates oxysterol interference of HepG2 cell cycle |
| |
Authors: | Wenbin Zhong You Zhou Jiwei Li Raghavendra Mysore Wei Luo Shiqian Li Mau-Sun Chang Vesa M. Olkkonen Daoguang Yan |
| |
Affiliation: | 1. Department of Biotechnology, Jinan University, Guangzhou 510632, China;2. Minerva Foundation Institute for Medical Research, Helsinki, Finland;3. Institute of Biochemical Sciences, National Taiwan University, No. 1, Taipei, Taiwan |
| |
Abstract: | ![]() We earlier identified OSBP-related protein 8 (ORP8) as an endoplasmic reticulum/nuclear envelope oxysterol-binding protein implicated in cellular lipid homeostasis, migration, and organization of the microtubule cytoskeleton. Here, a yeast two-hybrid screen identified Homo sapiens sperm associated antigen 5 (SPAG5)/Astrin as interaction partner of ORP8. The putative interaction was further confirmed by pull-down and co-immunoprecipitation assays. ORP8 did not colocalize with kinetochore-associated SPAG5 in mitotic HepG2 or HuH7 cells, but overexpressed ORP8 was capable of recruiting SPAG5 onto endoplasmic reticulum membranes in interphase cells. In our experiments, 25-hydroxycholesterol (25OHC) retarded the HepG2 cell cycle, causing accumulation in G2/M phase; ORP8 overexpression resulted in the same phenotype. Importantly, ORP8 knock-down dramatically inhibited the oxysterol effect on HepG2 cell cycle, suggesting a mediating role of ORP8. Furthermore, knock-down of SPAG5 significantly reduced the effects of both ORP8 overexpression and 25OHC on the cell cycle, placing SPAG5 downstream of the two cell-cycle interfering factors. Taken together, the present results suggest that ORP8 may via SPAG5 mediate oxysterol interference of the HepG2 cell cycle. |
| |
Keywords: | Astrin Cell cycle 25-Hydroxycholesterol ORP8 Oxysterol-binding protein SPAG5 |
本文献已被 ScienceDirect 等数据库收录! |
|