Golgi vesicle proteins are linked to the assembly of an actin complex defined by mAbp1.
Recent studies indicate that regulation of the actin cytoskeleton is important for protein trafficking, but its precise role is unclear. We have characterized the ARF1-dependent assembly of actin on the Golgi apparatus. Actin recruitment involves Cdc42/Rac and requires the activation of the Arp2/3 complex. Although the actin-binding proteins mAbp1 (SH3p7) and drebrin share sequence homology, they are differentially segregated into two distinct ARF-dependent actin complexes. The binding of Cdc42 and mAbp1, which localize to the Golgi apparatus, but not drebrin, is blocked by occupation of the p23 cargo-protein-binding site on coatomer. Exogenously expressed mAbp1 is mislocalized and inhibits Golgi transport in whole cells. The ability of ARF, vesicle-coat proteins, and cargo to direct the assembly of cytoskeletal structures helps explain how only a handful of vesicle types can mediate the numerous trafficking steps in the cell.
Fucini
Raymond V
RV
Department of Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
Chen
Ji-Long
JL
Sharma
Catherine
C
Kessels
Michael M
MM
Stamnes
Mark
M
D020823:ADP-Ribosylation Factor 1 / Q000502:physiology; D000199:Actins / Q000502:physiology*; D000818:Animals; D002417:Cattle; D003599:Cytoskeleton / Q000502:physiology; D006056:Golgi Apparatus / Q000502:physiology*; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000502:physiology*; D008840:Microfilament Proteins / Q000502:physiology*; D051381:Rats; D022142:Secretory Vesicles / Q000502:physiology; D020764:cdc42 GTP-Binding Protein / Q000502:physiology; D020741:rho GTP-Binding Proteins / Q000502:physiology; D018909:src Homology Domains
D000199:Actins; C485513:Dbnl protein, rat; D046911:Macromolecular Substances; D008565:Membrane Proteins; D008840:Microfilament Proteins; D020823:ADP-Ribosylation Factor 1; D020764:cdc42 GTP-Binding Protein; D020741:rho GTP-Binding Proteins