RRC ID 6298
Author Derivery E, Fink J, Martin D, Houdusse A, Piel M, Stradal TE, Louvard D, Gautreau A.
Title Free Brick1 is a trimeric precursor in the assembly of a functional wave complex.
Journal PLoS One
Abstract BACKGROUND:The Wave complex activates the Arp2/3 complex, inducing actin polymerization in lamellipodia and membrane ruffles. The Wave complex is composed of five subunits, the smallest of which, Brick1/Hspc300 (Brk1), is the least characterized. We previously reported that, unlike the other subunits, Brk1 also exists as a free form.
PRINCIPAL FINDINGS:Here we report that this free form of Brk1 is composed of homotrimers. Using a novel assay in which purified free Brk1 is electroporated into HeLa cells, we were able to follow its biochemical fate in cells and to show that free Brk1 becomes incorporated into the Wave complex. Importantly, incorporation of free Brk1 into the Wave complex was blocked upon inhibition of protein synthesis and incorporated Brk1 was found to associate preferentially with neosynthesized subunits. Brk1 depleted HeLa cells were found to bleb, as were Nap1, Wave2 or ARPC2 depleted cells, suggesting that this blebbing phenotype of Brk1 depleted cells is due to an impairment of the Wave complex function rather than a specific function of free Brk1. Blebs of Brk1 depleted cells were emitted at sites where lamellipodia and membrane ruffles were normally emitted. In Brk1 depleted cells, the electroporation of free Brk1 was sufficient to restore Wave complex assembly and to rescue the blebbing phenotype.
CONCLUSION:Together these results establish that the free form of Brk1 is an essential precursor in the assembly of a functional Wave complex.
Volume 3(6)
Pages e2462
Published 2008-6-18
DOI 10.1371/journal.pone.0002462
PMID 18560548
PMC PMC2413427
MeSH Amino Acid Sequence Biopolymers Cell Line Cytoskeletal Proteins / chemistry Cytoskeletal Proteins / physiology* Electrophoresis, Polyacrylamide Gel Electroporation Humans Immunoprecipitation Molecular Sequence Data Transfection
IF 2.74
Times Cited 44
WOS Category CELL BIOLOGY
Resource
Arabidopsis / Cultured plant cells, genes pda00573