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Regulation of ALIX ubiquitination and function in GPCR lysosomal sorting by the alpha‐arrestin ARRDC3 (604.3)
Author(s) -
Lin Huilan,
Dores Michael,
Trejo JoAnn
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.604.3
Subject(s) - ubiquitin , endosome , microbiology and biotechnology , escrt , nedd4 , deubiquitinating enzyme , arrestin , ubiquitin ligase , chemistry , tsg101 , proteasome , g protein coupled receptor , biology , signal transduction , biochemistry , gene , intracellular , microvesicles , microrna
We recently discovered that protease‐activated receptor‐1 (PAR1), a GPCR for thrombin, is sorted to lysosomes through an ALIX‐mediated pathway independent of receptor ubiquitination. The mechanisms responsible for regulation of ALIX‐mediated ubiquitin‐independent sorting of GPCRs are not known. Here, we show that the arrestin‐domain containing protein‐3 (ARRDC3) is a key regulator of ALIX‐dependent lysosomal sorting of PAR1. We found that activated PAR1 internalized and colocalized with ALIX and ARRDC3 on late endosomes/lysosomes in HeLa cells. ARRDCs, also known as α‐arrestins, contain PPXY motifs within the C‐terminus that mediate interaction with E3 ubiquitin ligases. Co‐expression of an ARRDC3 C‐terminal truncation mutant lacking the PPXY motifs or mutant in which the PPXY motif was mutated to AAXA resulted in mislocalization of ARRDC3 and disruption of agonist‐induced PAR1 lysosomal sorting. Depletion of ARRDC3 by siRNA also inhibited activated PAR1‐induced ALIX ubiquitination. Thus, ARRDC3 may regulate ALIX activity by controlling the ubiquitination status of ALIX through the recruitment of E3 ubiquitin ligases and consequently regulate activated PAR1 sorting into intraluminal vesicles of late endosomes/multivesicular bodies Grant Funding Source : Supported by GM090689