The Vesicle Protein SAM-4 Regulates the Processivity of Synaptic Vesicle Transport

Qun Zheng, Shikha Ahlawat, Anneliese Schaefer, Tim Mahoney, Sandhya P. Koushika, Michael L. Nonet; 2014 PLoS Genetics, 10(10), 15p Read More


Axonal transport of synaptic vesicles (SVs) is a KIF1A/UNC-104 mediated process critical for synapse development and maintenance yet little is known of how SV transport is regulated. Using C. elegans as an in vivo model, we identified SAM-4 as a novel conserved vesicular component regulating SV transport. Processivity, but not velocity, of SV transport was reduced in sam-4 mutants. sam-4 displayed strong genetic interactions with mutations in the cargo binding but not the motor domain of unc-104. Gain-of-function mutations in the unc-104 motor domain, identified in this study, suppress the sam-4 defects by increasing processivity of the SV transport. Genetic analyses suggest that SAM-4, SYD-2/liprin-α and the KIF1A/UNC-104 motor function in the same pathway to regulate SV transport. Our data support a model in which the SV protein SAM-4 regulates the processivity of SV transport.

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Posted on November 24, 2014
Posted in: Axon Injury & Repair, Publications Authors: