| Summary: | 博士 === 慈濟大學 === 醫學科學研究所 === 106 === LIM domain only 7 (LMO7) is an actin filament-associated protein, that also binds to -actinin and AF6/afadin at the adhesion junction. In this study, we found that LMO7 was phosphorylated in nocodazole-arrested mitotic cells. This suggested that LMO7 has a role in mitosis progression. We demonstrate that LMO7 could localize to the actin filament; however, the LIM domain is not an actin-binding domain. Although LMO7 was found to interact with MAD1, LMO7 and MAD1 did not colocalize at kinetochores in prometaphase cells. Furthermore, the overexpression of both LMO7 and LIM peptides causes a spindle assembly checkpoint defect. We also found that LIM peptide colocalizes with MAD1 at kinetochores in prometaphase cells and at spindle poles in metaphase cells. Our findings reveal that MAD2 and BUBR1 failed to localize to kinetochores when the cells overexpressed LMO7 or LIM peptide. Finally, we found that s-afadin but not l-afadin significantly alleviated the spindle assembly checkpoint (SAC) defect caused by the overexpression of LMO7 or LIM peptide. In conclusion, we proved that the overexpression of LMO7 caused a SAC defect by interfering in MAD2 and BUBR1 localization.
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