The I-BAR protein Ivy1 is an effector of the Rab7 GTPase Ypt7 involved in vacuole membrane homeostasis

Johannes Numrich, Marie-Pierre Péli-Gulli, Henning Arlt, Alessandro Sardu, Janice Griffith, Tim Levine, Siegfried Engelbrecht-Vandré, Fulvio Reggiori, Claudio De Virgilio, Christian Ungermann

OnderzoeksoutputAcademicpeer review

38 Citaten (Scopus)
255 Downloads (Pure)


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.
Originele taal-2English
Pagina's (van-tot)2278-92
Aantal pagina's15
TijdschriftJournal of Cell Science
Nummer van het tijdschrift13
StatusPublished - 1-jul.-2015
Extern gepubliceerdJa


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