Physicochemical properties of the vacuolar membrane and cellular factors determine formation of vacuolar invaginations

• Published in: Scientific reports Vol. 13; no. 1; p. 16187
• Main Authors: Kimura, Yoko, Tsuji, Takuma, Shimizu, Yosuke, Watanabe, Yuki, Kimura, Masafumi, Fujimoto, Toyoshi, Higuchi, Miyuki
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27-09-2023; Nature Publishing Group; Nature Portfolio
• Subjects: 631/208; 631/326; 631/80; Autophagy; Genetic analysis; Heat; Heat tolerance; High temperature; Humanities and Social Sciences; Invaginations; Lipids; Localization; Membrane proteins; Membranes; Morphology; multidisciplinary; Mutants; Oxidative stress; Phenotypes; Physicochemical properties; Proteins; Science; Science (multidisciplinary); Temperature; Temperature effects; Vacuoles; Yeasts
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-43232-5

Vacuoles change their morphology in response to stress. In yeast exposed to chronically high temperatures, vacuolar membranes get deformed and invaginations are formed. We show that phase-separation of vacuolar membrane occurred after heat stress leading to the formation of the invagination. In addition, Hfl1, a vacuolar membrane-localized Atg8-binding protein, was found to suppress the excess vacuolar invaginations after heat stress. At that time, Hfl1 formed foci at the neck of the invaginations in wild-type cells, whereas it was efficiently degraded in the vacuole in the
atg8
Δ mutant. Genetic analysis showed that the endosomal sorting complex required for transport machinery was necessary to form the invaginations irrespective of Atg8 or Hfl1. In contrast, a combined mutation with the vacuole BAR domain protein Ivy1 led to vacuoles in
hfl1
Δ
ivy1
Δ and
atg8
Δ
ivy1
Δ mutants having constitutively invaginated structures; moreover, these mutants showed stress-sensitive phenotypes. Our findings suggest that vacuolar invaginations result from the combination of changes in the physiochemical properties of the vacuolar membrane and other cellular factors.