The I-BAR protein Ivy1 is an effector of the Rab7 GTPase Ypt7 involved in vacuole membrane homeostasis
Autor(en): | Numrich, Johannes Peli-Gulli, Marie-Pierre Arlt, Henning Sardu, Alessandro Griffith, Janice Levine, Tim Engelbrecht-Vandre, Siegfried Reggiori, Fulvio De Virgilio, Claudio Ungermann, Christian |
Stichwörter: | AUTOPHAGOSOME FORMATION; BINDING PROTEIN; Cell Biology; CONTROLS TORC1; EGO COMPLEX; HOMOTYPIC FUSION; HOPS TETHERING COMPLEX; Ivy1; LYSOSOMAL SURFACE; NUCLEOTIDE EXCHANGE; SNARE CHAPERONES; TORC1; Vacuole biogenesis; Vps33; YEAST SACCHAROMYCES-CEREVISIAE; Ypt7 | Erscheinungsdatum: | 2015 | Herausgeber: | COMPANY OF BIOLOGISTS LTD | Journal: | JOURNAL OF CELL SCIENCE | Volumen: | 128 | Ausgabe: | 13 | Startseite: | 2278 | Seitenende: | 2292 | Zusammenfassung: | Membrane fusion at the vacuole depends on a conserved machinery that includes SNAREs, the Rab7 homolog Ypt7 and its effector HOPS. Here, we demonstrate that Ypt7 has an unexpected additional function by controlling membrane homeostasis and nutrient-dependent signaling on the vacuole surface. We show that Ivy1, the yeast homolog of mammalian missing-in-metastasis (MIM), is a vacuolar effector of Ypt7-GTP and interacts with the EGO/ragulator complex, an activator of the target of rapamycin kinase complex 1 (TORC1) on vacuoles. Loss of Ivy1 does not affect EGO vacuolar localization and function. In combination with the deletion of individual subunits of the V-ATPase, however, we observed reduced TORC1 activity and massive enlargement of the vacuole surface. Consistent with this, Ivy1 localizes to invaginations at the vacuole surface and on liposomes in a phosphoinositide- and Ypt7-GTP-controlled manner, which suggests a role in microautophagy. Our data, thus, reveal that Ivy1 is a novel regulator of vacuole membrane homeostasis with connections to TORC1 signaling. |
ISSN: | 00219533 | DOI: | 10.1242/jcs.164905 |
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geprüft am 18.05.2024