RILP regulates vacuolar ATPase through interaction with the V1G1 subunit.
Rab-interacting lysosomal protein (RILP) is a downstream effector of the Rab7 GTPase. GTP-bound Rab7 recruits RILP to endosomal membranes and, together, they control late endocytic traffic, phagosome and autophagosome maturation and are responsible for signaling receptor degradation. We have identified, using different approaches, the V1G1 (officially known as ATP6V1G1) subunit of the vacuolar ATPase (V-ATPase) as a RILP-interacting protein. V1G1 is a component of the peripheral stalk and is fundamental for correct V-ATPase assembly. We show here that RILP regulates the recruitment of V1G1 to late endosomal and lysosomal membranes but also controls V1G1 stability. Indeed, we demonstrate that V1G1 can be ubiquitylated and that RILP is responsible for proteasomal degradation of V1G1. Furthermore, we demonstrate that alterations in V1G1 expression levels impair V-ATPase activity. Thus, our data demonstrate for the first time that RILP regulates the activity of the V-ATPase through its interaction with V1G1. Given the importance of V-ATPase in several cellular processes and human diseases, these data suggest that modulation of RILP activity could be used to control V-ATPase function.
Department of Biological and Environmental Sciences and Technologies, (DiSTeBA) University of Salento, Via Provinciale Monteroni 165, 73100 Lecce, Italy.
Maria
M
De Luca
Department of Biological and Environmental Sciences and Technologies, (DiSTeBA) University of Salento, Via Provinciale Monteroni 165, 73100 Lecce, Italy.
Laura
L
Cogli
Department of Biological and Environmental Sciences and Technologies, (DiSTeBA) University of Salento, Via Provinciale Monteroni 165, 73100 Lecce, Italy.
Cinzia
C
Progida
Department of Biological and Environmental Sciences and Technologies, (DiSTeBA) University of Salento, Via Provinciale Monteroni 165, 73100 Lecce, Italy.
Veronica
V
Nisi
IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy.
Roberta
R
Pascolutti
IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy.
Sara
S
Sigismund
IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy.
Pier Paolo
PP
Di Fiore
Department of Biological and Environmental Sciences and Technologies, (DiSTeBA) University of Salento, Via Provinciale Monteroni 165, 73100 Lecce, Italy cecilia.bucci@unisalento.it.
Cecilia
C
Bucci
D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology*; D000072159:Dynactin Complex; D011992:Endosomes / Q000201:enzymology; D015870:Gene Expression; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000201:enzymology*; D008247:Lysosomes / Q000201:enzymology; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011485:Protein Binding; D025941:Protein Interaction Mapping; D021122:Protein Subunits / Q000378:metabolism; D021381:Protein Transport; D059748:Proteolysis; D054875:Ubiquitination; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000378:metabolism; D000090802:rab7 GTP-Binding Proteins
D048868:Adaptor Proteins, Signal Transducing; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D021122:Protein Subunits; C423317:RILP protein, human; D000090802:rab7 GTP-Binding Proteins; C000716463:rab7 GTP-binding proteins, human; D046988:Proteasome Endopeptidase Complex; C000594810:ATP6V1G1 protein, human; D025262:Vacuolar Proton-Translocating ATPases; D020691:rab GTP-Binding Proteins
RILP; Rab7; Ubiquitin; V1G1; Vacuolar ATPase