SUMO-Conjugated RanGAP1 Plays A Role in Autophagy of both Lens Epithelial and Retinal Pigment Epithelial Cells

Abstract

Purpose: RanGAP1 is major lens protein localized in the nuclear pore complexes. Whether RanGAP1 plays a role in autophagy during eye development remains unknown. The present study presents evidence to show that the normal level of RanGAP1 plays an important role in maintaining physiological functions of both lens epithelial and retinal pigment epithelial cells.

Methods: Immunocytochemistry and western blot analysis were used to detect the expression level and localization of RanGAP1 in lens epithelial and pigment epithelial cells. ShRNA-mediated knockdown of RanGAP1 and pEGFP-RanGAP1-mediated overexpression were used to change the expression levels of RanGAP1. The expression levels and patterns of LC3, an autophagosome marker under different conditions of RanGAP1 were used to detect autophagy.

Results: SiRNA can efficiently knockdown RanGAP1 and pEGFP-RanGAP1 transfection can upregulate RanGAP1. Changes in the level of RanGAP1 expression and its sumoylation status cause significant changes in the ratio of LC3II verse LC3I, and their localization patterns in both lens epithelial and retinal pigment epithelial cells.

Conclusions: RanGAP1 plays important functions in regulating cell metabolism in ocular lens and retina. Disruption of its functions induces autophagy of both lens epithelial and retinal pigment epithelial cells.

Keywords: 497 development • 714 signal transduction • 445 cataract