TY - JOUR
T1 - The RickA protein of Rickettsia conorii activates the Arp2/3 complex
AU - Gouin, Edith
AU - Egile, Coumaran
AU - Dehoux, Pierre
AU - Villiers, Veronique
AU - Adams, Josephine
AU - Gertler, Frank
AU - Li, Rong
AU - Cossart, Pascale
N1 - Funding Information:
Acknowledgements WethankM.VetterandmembersoftheMaricqlaboratoryforcommentson the manuscript; L. Jack for generating transgenic strains; C. Walker, N. Strutz, M. Francis and A. Ebens for discussions; C. Rongo and J. Kaplan for the nuIs25 strain; and A. Gottschalk and W. Schafer for help with immunolabelling live worms. Some strains were provided by the Caenorhabditis Genetics Center. This research was supported by the Burroughs Wellcome Foundation, and by a grant from the NIH.
Funding Information:
Acknowledgements We thank L. Blanchoin for help and discussions, L. Machesky for the gift of plasmids Scar-WA and ScarW, and P. Renesto and all members of the Cossart laboratory for discussions and suggestions. This work was supported by the Pasteur Institute, the Ministère de la Recherche et de la Technologie (Programme PRFMMIP) and the Direction Générale des Armées (DGA). C.E. is supported by a Human Frontier Science programme fellowship. P.C. is an international scholar from the Howard Hughes Medical Institute.
PY - 2004/1/29
Y1 - 2004/1/29
N2 - Actin polymerization, the main driving force for cell locomotion, is also used by the bacteria Listeria and Shigella and vaccinia virus for intracellular and intercellular movements. Seminal studies have shown the key function of the Arp2/3 complex in nucleating actin and generating a branched array of actin filaments during membrane extension and pathogen movement. Arp2/3 requires activation by proteins such as the WASP-family proteins or ActA of Listeria. We previously reported that actin tails of Rickettsia conorii, another intracellular bacterium, unlike those of Listeria, Shigella or vaccinia, are made of long unbranched actin filaments apparently devoid of Arp2/3 (ref. 4). Here we identify a R. conorii surface protein, RickA, that activates Arp2/3 in vitro, although less efficiently than ActA. In infected cells, Arp2/3 is detected on the rickettsial surface but not in actin tails. When expressed in mammalian cells and targeted to the membrane, RickA induces filopodia. Thus RickA-induced actin polymerization, by generating long actin filaments reminiscent of those present in filopodia, has potential as a tool for studying filopodia formation.
AB - Actin polymerization, the main driving force for cell locomotion, is also used by the bacteria Listeria and Shigella and vaccinia virus for intracellular and intercellular movements. Seminal studies have shown the key function of the Arp2/3 complex in nucleating actin and generating a branched array of actin filaments during membrane extension and pathogen movement. Arp2/3 requires activation by proteins such as the WASP-family proteins or ActA of Listeria. We previously reported that actin tails of Rickettsia conorii, another intracellular bacterium, unlike those of Listeria, Shigella or vaccinia, are made of long unbranched actin filaments apparently devoid of Arp2/3 (ref. 4). Here we identify a R. conorii surface protein, RickA, that activates Arp2/3 in vitro, although less efficiently than ActA. In infected cells, Arp2/3 is detected on the rickettsial surface but not in actin tails. When expressed in mammalian cells and targeted to the membrane, RickA induces filopodia. Thus RickA-induced actin polymerization, by generating long actin filaments reminiscent of those present in filopodia, has potential as a tool for studying filopodia formation.
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U2 - 10.1038/nature02318
DO - 10.1038/nature02318
M3 - Article
C2 - 14749835
AN - SCOPUS:0842263990
SN - 0028-0836
VL - 427
SP - 457
EP - 461
JO - Nature
JF - Nature
IS - 6973
ER -