Structure Elucidation of the Rho-GTPhase Activating DH-Homology Domain
Abstract
Rho-family of small GTPases transduce signals from receptors to modulate various physiological responses including cytoskeletal reorganization leading to changes in cell shape and motility, mitogenesis and development. Proteins containing the Dbl homology (DR) domain are responsible for activating Rho GTPases by catalyzing the exchange of GDP for GTP. The mechanism of DR domain stimulation by receptors remains largely unknown however. For the Dbl protein Vav, this mechanism involves tyrosine phosphorylation, resulting in increased nucleotide exchange activity in vivo. We show through structure determination that the mVav1 DR domain is autoinhibited by an N- terminal extension, which lies in the GTPase interaction site. This extension contains the Tyr174 Src-family kinase recognition site, and phosphorylation of this residue, as well as truncation of the peptide, results in stimulation of GEF activity. NMR spectroscopy data show that the N-terminal peptide is released from the DR domain and becomes unstructured upon phosphorylation. Thus, tyrosine phosphorylation relieves autoinhibition by exposing the GTPase interaction surface of the DR domain, which is obligatory for Vav activation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2000
- Accession Number
- ADA389743
Entities
People
- Behzad Aghazadeh
- Michael K. Rosen
Organizations
- Memorial Sloan Kettering Cancer Center