Secretory autophagy-promoted cargo exocytosis requires active RAB37

Shan Ying Wu, Yi Ching Wang, Roberto Zuchini, Kai Ying Lan, Hsiao Sheng Liu, Sheng Hui Lan

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

RAB37 GTPase regulates cargo exocytosis by cycling between an inactive GDP-bound form and an active GTP-bound form. We reveal that RAB37 simultaneously regulates autophagy activation and tissue inhibitor of metalloproteinase 1 (TIMP1) secretion in lung cancer cells under starvation conditions. TIMP1, an inflammatory cytokine, is a known inhibitory molecule of matrix metalloproteinases matrix metalloproteinase 9 and suppresses the mobility of lung cancer cells both in vitro and in vivo through conventional exocytosis under serum-free conditions. Notably, we disclosed that secretory autophagy participates in TIMP1 secretion in a RAB37- and Sec22b-dependent manner. Sec22b, a SNARE family protein, participates in vesicle and membrane fusion of secretory autophagy. Knockdown of Sec22b decreased TIMP1 secretion and cell motility but did not affect cell proliferation under starvation conditions. We confirmed that starvation-activated RAB37 accompanied by Sec22b is essential for secretory autophagy to further enhance TIMP1 exocytosis. We further use an off-label drug amiodarone to demonstrate that autophagy induction facilitates TIMP1 secretion and suppresses the motility and metastasis of lung cancer cells in a RAB37-dependent manner in the lung-to-lung mouse model. In conclusion, we demonstrated that the RAB37 activation plays a pivotal regulatory role in secretory autophagy for TIMP1 secretion in lung cancer. Abbreviations: ATG: autophagy-related gene; GDP: guanosine diphosphate; GTP: guanosine triphosphate; LC3: microtubule-associated protein 1A/1B-light chain 3; SNARE: soluble N-ethylmaleimide-sensitive-factor attachment protein receptor; TIMP1: tissue inhibitor matrix metalloproteinase 1.

Original languageEnglish
Pages (from-to)933-934
Number of pages2
JournalAutophagy
Volume20
Issue number4
DOIs
Publication statusPublished - 2024

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

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