TY - JOUR
T1 - Dynamin2 and cortactin regulate actin assembly and filament organization
AU - Schafer, Dorothy A.
AU - Weed, Scott A.
AU - Binns, Derk
AU - Karginov, Andrei V.
AU - Parsons, J. Thomas
AU - Cooper, John A.
N1 - Funding Information:
This work was supported by National Institutes of Health (NIH) GM 38542 to J.A.C., by NIH-NCI CA29243 to J.T.P., by NIH GM55562 to J.P. Albanesi, and by start-up funds from the University of Virginia to D.A.S. S.A.W. is a member of the University of Colorado Cancer Center. We are grateful to Drs. Kazuhisa Nakayama and Mark McNiven for plasmids for expression of dynamin2 and dynamin2 K44A, to Dr. Pietro DeCamilli for anti-dynamin2 and plasmids for expression of amphiphysin1 SH3 domain, to Dr. Anders Carlsson for developing the method for quantifying actin dynamics in vivo using the fluctuation of GFP-CP fluorescence in live cells, to Dr. Martin Wear for the supply of Arp2/3 complex, and for the technical assistance of Tanya Kotova and Anna Sargeant.
PY - 2002/10/29
Y1 - 2002/10/29
N2 - The GTPase dynamin is required for endocytic vesicle formation. Dynamin has also been implicated in regulating the actin cytoskeleton, but the mechanism by which it does so is unclear [1-4]. Through interactions via its proline-rich domain (PRD), dynamin binds several proteins, including cortactin [1], profilin [5], syndapin [6], and murine Abp1 [7], that regulate the actin cytoskeleton. We investigated the interaction of dynamin2 and cortactin in regulating actin assembly in vivo and in vitro. When expressed in cultured cells, a dynamin2 mutant with decreased affinity for GTP decreased actin dynamics within the cortical actin network. Expressed mutants of cortactin that have decreased binding of Arp2/3 complex or dynamin2 also decreased actin dynamics. Dynamin2 influenced actin nucleation by purified Arp2/3 complex and cortactin in vitro in a biphasic manner. Low concentrations of dynamin2 enhanced actin nucleation by Arp2/3 complex and cortactin, and high concentrations were inhibitory. Dynamin2 promoted the association of actin filaments nucleated by Arp2/3 complex and cortactin with phosphatidylinositol 4,5-bisphosphate (PIP2)-containing lipid vesicles. GTP hydrolysis altered the organization of the filaments and the lipid vesicles. We conclude that dynamin2, through an interaction with cortactin, regulates actin assembly and actin filament organization at membranes.
AB - The GTPase dynamin is required for endocytic vesicle formation. Dynamin has also been implicated in regulating the actin cytoskeleton, but the mechanism by which it does so is unclear [1-4]. Through interactions via its proline-rich domain (PRD), dynamin binds several proteins, including cortactin [1], profilin [5], syndapin [6], and murine Abp1 [7], that regulate the actin cytoskeleton. We investigated the interaction of dynamin2 and cortactin in regulating actin assembly in vivo and in vitro. When expressed in cultured cells, a dynamin2 mutant with decreased affinity for GTP decreased actin dynamics within the cortical actin network. Expressed mutants of cortactin that have decreased binding of Arp2/3 complex or dynamin2 also decreased actin dynamics. Dynamin2 influenced actin nucleation by purified Arp2/3 complex and cortactin in vitro in a biphasic manner. Low concentrations of dynamin2 enhanced actin nucleation by Arp2/3 complex and cortactin, and high concentrations were inhibitory. Dynamin2 promoted the association of actin filaments nucleated by Arp2/3 complex and cortactin with phosphatidylinositol 4,5-bisphosphate (PIP2)-containing lipid vesicles. GTP hydrolysis altered the organization of the filaments and the lipid vesicles. We conclude that dynamin2, through an interaction with cortactin, regulates actin assembly and actin filament organization at membranes.
UR - http://www.scopus.com/inward/record.url?scp=0037195267&partnerID=8YFLogxK
U2 - 10.1016/S0960-9822(02)01228-9
DO - 10.1016/S0960-9822(02)01228-9
M3 - Article
C2 - 12419186
AN - SCOPUS:0037195267
SN - 0960-9822
VL - 12
SP - 1852
EP - 1857
JO - Current Biology
JF - Current Biology
IS - 21
ER -