Targeted disruption of GAK stagnates autophagic flux by disturbing lysosomal dynamics

MASAYA MIYAZAKI, MASAKI HIRAMOTO, NAOHARU TAKANO, HIROKO KOKUBA, JUN TAKEMURA, MAYUMI TOKUHISA, HIROTSUGU HINO, HIROMI KAZAMA, KEISUKE MIYAZAWA

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

The autophagy-lysosome system allows cells to adapt to environmental changes by regulating the degradation and recycling of cellular components, and to maintain homeostasis by removing aggregated proteins and defective organelles. Cyclin G-associated kinase (GAK) is involved in the regulation of clathrin-dependent endocytosis and cell cycle progression. In addition, a single nucleotide polymorphism at the GAK locus has been reported as a risk factor for Parkinson's disease. However, the roles of GAK in the autophagy-lysosome system are not completely understood, thus the present study aimed to clarify this. In the present study, under genetic disruption or chemical inhibition of GAK, analyzing autophagic flux and observing morphological changes of autophagosomes and autolysosomes revealed that GAK controlled lysosomal dynamics via actomyosin regulation, resulting in a steady progression of autophagy. GAK knockout (KO) in A549 cells impaired autophagosome-lysosome fusion and autophagic lysosome reformation, which resulted in the accumulation of enlarged autophagosomes and autolysosomes during prolonged starvation. The stagnation of autophagic flux accompanied by these phenomena was also observed with the addition of a GAK inhibitor. Furthermore, the addition of Rho-associated protein kinase (ROCK) inhibitor or ROCK1 knockdown mitigated GAK KO-mediated effects. The results suggested a vital role of GAK in controlling lysosomal dynamics via maintaining lysosomal homeostasis during autophagy.

Original languageEnglish
Article number195
JournalInternational Journal of Molecular Medicine
Volume48
Issue number4
DOIs
Publication statusPublished - Oct 2021
Externally publishedYes

Keywords

  • Actomyosin
  • Autophagic lysosome reformation
  • Autophagosome-lysosome fusion
  • Autophagy
  • Cyclin G-associated kinase
  • Rho-associated protein kinase

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