Small GTP-binding protein TC10 differentially regulates two distinct populations of filamentous actin in 3T3L1 adipocytes.
TC10 is a member of the Rho family of small GTP-binding proteins that has previously been implicated in the regulation of insulin-stimulated GLUT4 translocation in adipocytes. In a manner similar to Cdc42-stimulated actin-based motility, we have observed that constitutively active TC10 (TC10/Q75L) can induce actin comet tails in Xenopus oocyte extracts in vitro and extensive actin polymerization in the perinuclear region when expressed in 3T3L1 adipocytes. In contrast, expression of TC10/Q75L completely disrupted adipocyte cortical actin, which was specific for TC10, because expression of constitutively active Cdc42 was without effect. The effect of TC10/Q75L to disrupt cortical actin was abrogated after deletion of the amino terminal extension (DeltaN-TC10/Q75L), whereas this deletion retained the ability to induce perinuclear actin polymerization. In addition, alteration of perinuclear actin by expression of TC10/Q75L, a dominant-interfering TC10/T31N mutant or a mutant N-WASP protein (N-WASP/DeltaVCA) reduced the rate of VSV G protein trafficking to the plasma membrane. Furthermore, TC10 directly bound to Golgi COPI coat proteins through a dilysine motif in the carboxyl terminal domain consistent with a role for TC10 regulating actin polymerization on membrane transport vesicles. Together, these data demonstrate that TC10 can differentially regulate two types of filamentous actin in adipocytes dependent on distinct functional domains and its subcellular compartmentalization.
Department of Physiology and Biophysics, The University of Iowa, Iowa City, Iowa 52242, USA.
Makoto
M
Kanzaki
Robert T
RT
Watson
June Chunqiu
JC
Hou
Mark
M
Stamnes
Alan R
AR
Saltiel
Jeffrey E
JE
Pessin
D016475:3T3 Cells; D000199:Actins / Q000378:metabolism*; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D020816:Amino Acid Motifs; D000818:Animals; D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000494:pharmacology; D001692:Biological Transport / Q000502:physiology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D016466:CHO Cells; D002467:Cell Nucleus / Q000378:metabolism; D020756:Coatomer Protein / Q000378:metabolism; D006224:Cricetinae; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D004789:Enzyme Activation; D006056:Golgi Apparatus / Q000378:metabolism; D051379:Mice; D008845:Microinjections; D018613:Microscopy, Confocal; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000502:physiology; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines; D013997:Time Factors; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D014982:Xenopus laevis; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
D000199:Actins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D020756:Coatomer Protein; D009419:Nerve Tissue Proteins; D013844:Thiazoles; D053778:Thiazolidines; C495772:Wasl protein, mouse; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; C031815:toxB protein, Clostridium difficile; C503260:Rhoq protein, mouse; D020764:cdc42 GTP-Binding Protein; D020741:rho GTP-Binding Proteins; C037068:latrunculin B