RGD Reference Report - Identification of mammalian Vps24p as an effector of phosphatidylinositol 3,5-bisphosphate-dependent endosome compartmentalization. - Rat Genome Database

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Identification of mammalian Vps24p as an effector of phosphatidylinositol 3,5-bisphosphate-dependent endosome compartmentalization.

Authors: Whitley, P  Reaves, BJ  Hashimoto, M  Riley, AM  Potter, BV  Holman, GD 
Citation: Whitley P, etal., J Biol Chem 2003 Oct 3;278(40):38786-95. Epub 2003 Jul 23.
RGD ID: 1299526
Pubmed: PMID:12878588   (View Abstract at PubMed)
DOI: DOI:10.1074/jbc.M306864200   (Journal Full-text)

Phosphatidylinositol 3,5-bisphosphate is a membrane lipid found in all eukaryotes so far studied but downstream effector proteins of this lipid have yet to be identified. Here we report the use of cDNA phage libraries in conjunction with synthetic biotinylated derivatives of phosphatidylinositol 3,5-bisphosphate in the identification of a mammalian phosphatidylinositol 3,5-bisphosphate-binding protein, mVps24p. This protein is orthologous to the Saccharomyces cerevisiae protein, Vps24p, a class-E vacuolar protein-sorting protein. Using in vitro liposome binding and competition assays, we demonstrate that mVps24p selectively binds to phosphatidylinositol 3,5-bisphosphate and phosphatidylinositol 3,4-bisphosphate in preference to other phosphoinositides tested. When expressed in cultured mammalian cells, full-length mVps24p is cytosolic. However, when cells expressing the full-length mVps24p are co-transfected with a mutated form of mVps4p (which is defective in ATP hydrolysis), or when a N-terminal construct of mVps24p is expressed, the class-E cellular phenotype with swollen vacuoles is induced and mVps24p is membrane-associated. Furthermore, the accumulation of the N-terminal mVps24p construct on the swollen endosomal membranes is abrogated when phosphatidylinositol 3,5-bisphosphate synthesis is blocked with wortmannin. These data provide the first direct link between phosphatidylinositol 3,5-bisphosphate and the protein machinery involved in the production of the class-E cellular phenotype. We hypothesize that accumulation of Vps24 on membranes occurs when membrane association (dependent on interaction of phosphatidylinositol 3,5-bisphosphate with the N-terminal domain of the protein) is uncoupled from membrane disassociation (driven by Vps4p).

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
regulation of endosome size  IMP 1299526 RGD 

Molecular Function
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
phosphatidylinositol-4,5-bisphosphate binding  IMP 1299526 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Chmp3  (charged multivesicular body protein 3)

Objects referenced in this article
Gene CHMP3 charged multivesicular body protein 3 Homo sapiens

Additional Information