RRC ID 72404
Author Itakura E, Kishi C, Inoue K, Mizushima N.
Title Beclin 1 forms two distinct phosphatidylinositol 3-kinase complexes with mammalian Atg14 and UVRAG.
Journal Mol Biol Cell
Abstract Class III phosphatidylinositol 3-kinase (PI3-kinase) regulates multiple membrane trafficking. In yeast, two distinct PI3-kinase complexes are known: complex I (Vps34, Vps15, Vps30/Atg6, and Atg14) is involved in autophagy, and complex II (Vps34, Vps15, Vps30/Atg6, and Vps38) functions in the vacuolar protein sorting pathway. Atg14 and Vps38 are important in inducing both complexes to exert distinct functions. In mammals, the counterparts of Vps34, Vps15, and Vps30/Atg6 have been identified as Vps34, p150, and Beclin 1, respectively. However, orthologues of Atg14 and Vps38 remain unknown. We identified putative mammalian homologues of Atg14 and Vps38. The Vps38 candidate is identical to UV irradiation resistance-associated gene (UVRAG), which has been reported as a Beclin 1-interacting protein. Although both human Atg14 and UVRAG interact with Beclin 1 and Vps34, Atg14, and UVRAG are not present in the same complex. Although Atg14 is present on autophagic isolation membranes, UVRAG primarily associates with Rab9-positive endosomes. Silencing of human Atg14 in HeLa cells suppresses autophagosome formation. The coiled-coil region of Atg14 required for binding with Vps34 and Beclin 1 is essential for autophagy. These results suggest that mammalian cells have at least two distinct class III PI3-kinase complexes, which may function in different membrane trafficking pathways.
Volume 19(12)
Pages 5360-72
Published 2008-12-1
DOI 10.1091/mbc.e08-01-0080
PII E08-01-0080
PMID 18843052
PMC PMC2592660
MeSH Adaptor Proteins, Vesicular Transport / classification Adaptor Proteins, Vesicular Transport / genetics Adaptor Proteins, Vesicular Transport / metabolism* Amino Acid Sequence Androstadienes / metabolism Animals Apoptosis Regulatory Proteins / genetics Apoptosis Regulatory Proteins / metabolism* Autophagy / physiology Autophagy-Related Proteins Beclin-1 Cell Line Cell Membrane / metabolism Endocytosis / physiology Humans Membrane Proteins / genetics Membrane Proteins / metabolism* Mice Molecular Sequence Data Multiprotein Complexes / chemistry Multiprotein Complexes / metabolism* Phagosomes / metabolism Phagosomes / ultrastructure Phosphatidylinositol 3-Kinases / genetics Phosphatidylinositol 3-Kinases / metabolism* Phosphoinositide-3 Kinase Inhibitors Phylogeny RNA Interference Recombinant Fusion Proteins / genetics Recombinant Fusion Proteins / metabolism Sequence Alignment Signal Transduction / physiology Tumor Suppressor Proteins / genetics Tumor Suppressor Proteins / metabolism* Wortmannin rab GTP-Binding Proteins / genetics rab GTP-Binding Proteins / metabolism
IF 3.791
DNA material pEGFP-C1-hUVRAG (RDB19632) pMXs-puro-VPS34-GFP (RDB19633) p3xFLAG-CMV10-hUVRAG (RDB19776) pEGFP-C1-hAtg14 (RDB19785) pMXs-IP-GFP-Atg14 (RDB19790) pCI-neo-HA-hAtg14 (RDB19797) pCI-neo-HA-hUVRAG (RDB19803)