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Autophagy. 2009 May;5(4):534-6. Epub 2009 May 2.

Atg14 and UVRAG: mutually exclusive subunits of mammalian Beclin 1-PI3K complexes.

Author information

1
Department of Physiology and Cell Biology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japan.

Abstract

Vps34, a Class III phosphatidylinositol 3-kinase (PI3-kinase), produces phosphatidylinositol 3 phosphate (PI3P) and functions in various membrane traffic pathways including endocytosis, multivesicular body formation and autophagy. In mammalian cells, Vps34 forms a complex with Beclin 1, but it remains unclear how this Vps34 complex exerts its specific function on each membrane trafficking pathway. We recently identified mammalian Atg14, a new binding partner of the Vps34-Beclin 1 complex, using a computational approach. The Atg14 complex consists of Vps34, Beclin 1 and p150, but lacks UVRAG, which was previously reported to bind the Vps34-Beclin 1 complex. Atg14 localizes to isolation membrane/phagophore during starvation and is essential for autophagosome formation. In contrast, UVRAG primarily localizes to late endosomes. Since UVRAG shows homology with yeast Vps38, we speculate that it could be a mammalian Vps38 ortholog. These findings indicate that the Vps34-Beclin 1 complex has at least two distinct functions, which can be promoted by its binding partners Atg14 and UVRAG.

PMID:
19223761
[Indexed for MEDLINE]

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