Tuba, a GEF for CDC42, links dynamin to actin regulatory proteins

Methods Enzymol. 2005:404:537-45. doi: 10.1016/S0076-6879(05)04047-4.

Abstract

Tuba is a 178kD protein containing four NH2-terminal SH3 domains, a central Dbl homology (DH) domain followed by a BAR domain, and two COOH-terminal SH3 domains. The four NH2-terminal SH3 domains bind the GTPase dynamin, a protein critical for the fission of endocytic vesicles. The DH domain functions as a CDC42-specific guanine nucleotide exchange factor and is unique among DH domains because it is followed by a BAR domain rather than a PH domain. The COOH-terminal SH3 domain binds directly to N-WASP and Ena/VASP proteins, key regulatory proteins of the actin cytoskeleton, and recruits a larger protein complex comprising additional actin regulatory factors. The properties of Tuba provide new evidence for a functional link between dynamin, endocytosis, and actin. The presence of a BAR domain, rather than a PH domain, may reflect its action at high curvature regions of the plasma membrane. Its multiple binding sites for dynamin generate an exceptionally high avidity for this GTPase and make the NH2-terminal region of Tuba a very useful tool for the one-step purification of dynamin.

MeSH terms

  • Actins / metabolism*
  • Animals
  • Chromatography, Affinity
  • Cytoskeletal Proteins / physiology*
  • Dynamins / metabolism*
  • Glutathione Transferase / genetics
  • Guanine Nucleotide Exchange Factors / metabolism*
  • Humans
  • Liposomes / metabolism
  • Protein Structure, Tertiary
  • Rats
  • Recombinant Fusion Proteins / isolation & purification
  • cdc42 GTP-Binding Protein / metabolism*
  • src Homology Domains

Substances

  • Actins
  • Cytoskeletal Proteins
  • DNMBP protein, human
  • Guanine Nucleotide Exchange Factors
  • Liposomes
  • Recombinant Fusion Proteins
  • Glutathione Transferase
  • cdc42 GTP-Binding Protein
  • Dynamins