p150glued deficiency impairs effective fusion between autophagosomes and lysosomes due to their redistribution to the cell periphery

Dynein-dynactin has an indispensable role in autophagy and p150glued is the largest component of the dynactin complex. Here, we characterized the effects of knockdown (KD) of endogenous p150glued and of the pathogenic mutation of p150glued found in autosomal dominant p150glued-associated disorders [hereditary motor neuronopathy with vocal paresis (HMN7B) and Perry syndrome] on autophagy. Overexpression of the p150glued pathogenic mutant or siRNA KD of p150glued promoted the localization of lysosomes at the cell periphery and increased the number of autophagosomes, suggesting partial blockage of autophagic flux. Surprisingly, although autophagosomes and lysosomes were redistributed predominantly to the cell periphery in p150glued-KD cells, the autolysosome formation ratio was preserved. However, under autophagy activation conditions induced by starvation, the ratio of autophagosome-lysosome fusion in p150glued-KD cells was decreased in the early phase. Our data demonstrate that functional loss of p150glued may cause autophagic insufficiency, which may be associated with the pathogenesis of p150glued-associated disorders.