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The closure of Pak1‐dependent macropinosomes requires the phosphorylation of CtBP1/BARS
Author(s) -
Liberali Prisca,
Kakkonen Elina,
Turacchio Gabriele,
Valente Carmen,
Spaar Alexander,
Perinetti Giuseppe,
Böckmann Rainer A,
Corda Daniela,
Colanzi Antonino,
Marjomaki Varpu,
Luini Alberto
Publication year - 2008
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2008.59
Subject(s) - biology , phosphorylation , closure (psychology) , microbiology and biotechnology , pak1 , economics , market economy
Membrane fission is an essential process in membrane trafficking and other cellular functions. While many fissioning and trafficking steps are mediated by the large GTPase dynamin, some fission events are dynamin independent and involve C‐terminal‐binding protein‐1/brefeldinA‐ADP ribosylated substrate (CtBP1/BARS). To gain an insight into the molecular mechanisms of CtBP1/BARS in fission, we have studied the role of this protein in macropinocytosis, a dynamin‐independent endocytic pathway that can be synchronously activated by growth factors. Here, we show that upon activation of the epidermal growth factor receptor, CtBP1/BARS is (a) translocated to the macropinocytic cup and its surrounding membrane, (b) required for the fission of the macropinocytic cup and (c) phosphorylated on a specific serine that is a substrate for p21‐activated kinase, with this phosphorylation being essential for the fission of the macropinocytic cup. Importantly, we also show that CtBP1/BARS is required for macropinocytic internalization and infection of echovirus 1. These results provide an insight into the molecular mechanisms of CtBP1/BARS activation in membrane fissioning, and extend the relevance of CtBP1/BARS‐induced fission to human viral infection.