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Roles for L o microdomains and ESCRT in ER stress-induced lipid droplet microautophagy in budding yeast.
Liao, Pin-Chao; Garcia, Enrique J; Tan, Gary; Tsang, Catherine A; Pon, Liza A.
Afiliação
  • Liao PC; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032.
  • Garcia EJ; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032.
  • Tan G; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032.
  • Tsang CA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032.
  • Pon LA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032.
Mol Biol Cell ; 32(22): br12, 2021 12 01.
Article em En | MEDLINE | ID: mdl-34668753
ABSTRACT
Microlipophagy (µLP), degradation of lipid droplets (LDs) by microautophagy, occurs by autophagosome-independent direct uptake of LDs at lysosomes/vacuoles in response to nutrient limitations and ER stressors in Saccharomyces cerevisiae. In nutrient-limited yeast, liquid-ordered (Lo) microdomains, sterol-rich raftlike regions in vacuolar membranes, are sites of membrane invagination during LD uptake. The endosome sorting complex required for transport (ESCRT) is required for sterol transport during Lo formation under these conditions. However, ESCRT has been implicated in mediating membrane invagination during µLP induced by ER stressors or the diauxic shift from glycolysis- to respiration-driven growth. Here we report that ER stress induced by lipid imbalance and other stressors induces Lo microdomain formation. This process is ESCRT independent and dependent on Niemann-Pick type C sterol transfer proteins. Inhibition of ESCRT or Lo microdomain formation partially inhibits lipid imbalance-induced µLP, while inhibition of both blocks this µLP. Finally, although the ER stressors dithiothreitol or tunicamycin induce Lo microdomains, µLP in response to these stressors is ESCRT dependent and Lo microdomain independent. Our findings reveal that Lo microdomain formation is a yeast stress response, and stress-induced Lo microdomain formation occurs by stressor-specific mechanisms. Moreover, ESCRT and Lo microdomains play functionally distinct roles in LD uptake during stress-induced µLP.
Assuntos

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Saccharomyces cerevisiae / Microdomínios da Membrana / Gotículas Lipídicas / Microautofagia Idioma: En Ano de publicação: 2021 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Saccharomyces cerevisiae / Microdomínios da Membrana / Gotículas Lipídicas / Microautofagia Idioma: En Ano de publicação: 2021 Tipo de documento: Article