Open AccessA Rickettsia WASP‐like protein activates the Arp2/3 complex and mediates actin‐based motility
Author(s) -
Jeng Robert L.,
Goley Erin D.,
D’Alessio Joseph A.,
Chaga Oleg Y.,
Svitkina Tatyana M.,
Borisy Gary G.,
Heinzen Robert A.,
Welch Matthew D.
Publication year - 2004
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/j.1462-5822.2004.00402.x
Subject(s) - biology , actin , microbiology and biotechnology , motility
Summary Spotted fever group Rickettsia are obligate intracellular pathogens that exploit the host cell actin cytoskeleton to promote motility and cell‐to‐cell spread. Although other pathogens such as Listeria monocytogenes use an Arp2/3 complex‐dependent nucleation mechanism to generate comet tails consisting of Y‐branched filament arrays, Rickettsia polymerize tails consisting of unbranched filaments by a previously unknown mechanism. We identified genes in several Rickettsia species encoding proteins (termed RickA) with similarity to the WASP family of Arp2/3‐complex activators. Rickettsia rickettsii RickA activated both the nucleation and Y‐branching activities of the Arp2/3 complex like other WASP‐family proteins, and was sufficient to direct the motility of microscopic beads in cell extracts. Actin tails generated by RickA‐coated beads consisted of Y‐branched filament networks. These data suggest that Rickettsia use an Arp2/3 complex‐dependent actin‐nucleation mechanism similar to that of other pathogens. We propose that additional Rickettsia or host factors reorganize the Y‐branched networks into parallel arrays in a manner similar to a recently proposed model of filopodia formation.