Biology subjects

Arif, E.

Publications and source records attributed to Arif, E..

2 recordsLinked to original sources

bioRxiv2020

Motor Protein MYO1C is Critical for Photoreceptor Opsin Trafficking and Vision

Unconventional myosins linked to deafness are also proposed to play a role in retinal cell physiology. However, their direct role in photoreceptor function remains unclear. We demonstrate that systemic loss of the unconventional myosin MYO1C in mice specifically affected opsin trafficking, leading to loss of visual function. Electroretinogram analysis of Myo1c knockout (Myo1c-KO) mice showed a progressive loss of photoreceptor function. Immunohistochemistry and binding assays demonstrated MYO1C localization to photoreceptor inner and outer segments (OS) and identified a direct interaction of rhodopsin with the MYO1C cargo domain. In Myo1c-KO retinas, rhodopsin mislocalized to rod inner segments (IS) and cell bodies, while cone opsins in OS showed punctate staining. In aged mice, the histological and ultrastructural examination of the phenotype of Myo1c-KO retinas showed progressively shorter photoreceptor OS. These results demonstrate that MYO1C is critical for opsin trafficking to the photoreceptor OS and for normal visual function.

cell biology↗

bioRxiv2020

HGF-induced activation of NEPHRIN and NEPH1 serves as a novel mechanism for recovery of podocytes from injury

When activated, slit diaphragm proteins NEPHRIN and NEPH1 enable signaling pathways leading to podocyte actin cytoskeleton reorganization, which is critical for podocyte recovery from injury. However, the mechanisms through which these proteins are activated remain unknown. This study presents a novel concept showing ligand-induced activation of NEPHRIN and NEPH1. We first identified phosphatase SHP-2, which directly dephosphorylated these proteins. We next identified HGF, a known SHP-2 modulator, as a rapid inducer of NEPHRIN and NEPH1 phosphorylation. Using baculovirus expressed recombinant purified proteins, SPR (surface plasma resonance), molecular modeling and peptide binding approaches, we show that HGF directly binds NEPHRIN and NEPH1 extracellular domains. Further, using cultured podocytes and Drosophila nephrocytes, we demonstrate that while HGF treatment repaired injured podocytes, the addition of inhibitory NEPH1 or NEPHRIN peptides blocked HGF-induced recovery. Overall, this study shows novel activation and deactivation mechanisms for NEPHRIN and NEPH1 that are required for their function.

cell biology↗