Dynamics of the Dictyostelium Arp2/3 complex in endocytosis, cytokinesis, and chemotaxis.
The Arp2/3 complex is a ubiquitous and important regulator of the actin cytoskeleton. Here we identify this complex from Dictyostelium and investigate its dynamics in live cells. The predicted sequences of the subunits show a strong homology to the members of the mammalian complex, with the larger subunits generally better conserved than the smaller ones. In the highly motile cells of Dictyostelium, the Arp2/3 complex is rapidly re-distributed to the cytoskeleton in response to external stimuli. Fusions of Arp3 and p41-Arc with GFP reveal that in phagocytosis, macropinocytosis, and chemotaxis the complex is recruited within seconds to sites where actin polymerization is induced. In contrast, there is little or no localization to the cleavage furrow during cytokinesis. Rather the Arp2/3 complex is enriched in ruffles at the polar regions of mitotic cells, which suggests a role in actin polymerization in these ruffles.
Insall
R
R
School of Biosciences, Birmingham University, Birmingham, United Kingdom.
Müller-Taubenberger
A
A
Machesky
L
L
Köhler
J
J
Simmeth
E
E
Atkinson
S J
SJ
Weber
I
I
Gerisch
G
G
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000032:analysis / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division / Q000502:physiology*; D002633:Chemotaxis / Q000502:physiology*; D000242:Cyclic AMP / Q000494:pharmacology; D003598:Cytoskeletal Proteins; D004023:Dictyostelium / Q000737:chemistry*; D004705:Endocytosis / Q000502:physiology*; D011992:Endosomes / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006651:Histocytochemistry / Q000379:methods; D008164:Luminescent Proteins / Q000378:metabolism; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010587:Phagocytosis / Q000502:physiology; D010873:Pinocytosis; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013045:Species Specificity
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D003598:Cytoskeletal Proteins; D008164:Luminescent Proteins; D046911:Macromolecular Substances; D049452:Green Fluorescent Proteins; D000242:Cyclic AMP