Université de Fribourg

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

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

In: Journal of Cell Science, 2015, vol. 128, no. 13, p. 2278–2292

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...

Université de Fribourg

Leucyl-tRNA synthetase controls TORC1 via the EGO complex

Bonfils, Grégory ; Jaquenoud, Malika ; Bontron, Séverine ; Ostrowicz, Clemens ; Ungermann, Christian ; De Virgilio, Claudio

In: Molecular Cell, 2012, vol. 46, no. 1, p. 105–110

The target of rapamycin complex 1 (TORC1) is an essential regulator of eukaryotic cell growth that responds to growth factors, energy levels, and amino acids. The mechanisms through which the preeminent amino acid leucine signals to the TORC1-regulatory Rag GTPases, which activate TORC1 within the yeast EGO complex (EGOC) or the structurally related mammalian Rag-Ragulator complex, remain...

Université de Fribourg

Acyl-CoA-binding protein, Acb1p, is required for normal vacuole function and ceramide synthesis in Saccharomyces cerevisiae

Faergeman, Nils J. ; Feddersen, Søren ; Christiansen, Janne K. ; Larsen, Morten K. ; Schneiter, Roger ; Ungermann, Christian ; Mutenda, Kudzai ; Roepstroff, Peter ; Knudsen, Jens

In: Biochemical Journal, 2004, vol. 380, p. 907-918

In the present study, we show that depletion of acyl-CoA-binding protein, Acb1p, in yeast affects ceramide levels, protein trafficking, vacuole fusion and structure. Vacuoles in Acb1p-depleted cells are multi-lobed, contain significantly less of the SNAREs (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors) Nyv1p, Vam3p and Vti1p, and are unable to fuse in vitro. Mass...