RILP interacts with VPS22 and VPS36 of ESCRT-II and regulates their membrane recruitment.
RILP is emerging as a key regulator of late endocytic pathway by functioning as a downstream effector of activated Rab7 and Rab34, while ESCRT-I-->ESCRT-II-->ESCRT-III machinery acts in sorting proteins to the multivesicular body (MVB) initiated at the early/sorting endosome. We show here that the early machinery is integrated with the late machinery through a novel regulatory loop in which RILP interacts with VPS22 and VPS36 of ESCRT-II to mediate their membrane recruitment. The N-terminal and C-terminal half of RILP mediate interaction with VPS22 and VPS36, respectively. Overexpression of RILP leads to enlarged and clustered MVBs marked by lysobisphosphatidic acid (LBPA). In addition, RILP or its C-terminal fragment causes a retardation of sorting internalized EGF to the degradation route at the level of sorting endosomes marked by EEA1. We propose that RILP-->ESCRT-II serves as a regulatory/feedback loop to govern the coordination of early and late parts of the endocytic pathway.
Wang
Tuanlao
T
Membrane Biology Laboratory, Institute of Molecular and Cell Biology, Proteos, 61 Biopolis Drive, Singapore 138673, Singapore.
Hong
Wanjin
W
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D003593:Cytoplasm / Q000737:chemistry; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism* / Q000648:ultrastructure; D004815:Epidermal Growth Factor / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D004815:Epidermal Growth Factor