The structure of the membrane distal phosphatase domain of RPTPalpha reveals interdomain flexibility and an SH2 domain interaction region.
The receptor protein tyrosine phosphatase alpha (RPTPalpha) is a transmembrane receptor with two intracellular protein tyrosine phosphatase domains, a catalytically active membrane proximal domain (D1) and a membrane distal phosphatase domain with minimal catalytic activity (D2). Here we elucidate the crystal structure of RPTPalpha's D2 domain. Unlike D1, D2 exists as a monomer and lacks the N-terminal inhibitory wedge motif. The N-terminal portion of D2 is disordered, and this region linking D1 to D2 is proteolytically labile in solution whether part of D2 alone or tethered to D1, indicating that the polypeptide backbone of this part of D2 is highly flexible, and therefore accessible to proteases under native conditions. Furthermore, we have crystallized the SH2 domain of the protein tyrosine kinase c-Src, a RPTPalpha substrate, with a phosphopeptide encompassing the C-terminal phosphorylation site of D2 (pTyr789). The SH2 domain of Src binds RPTPalpha in an extended conformation. The structural and functional data support a D1-D2 arrangement with significant flexibility between phosphatase domains of RPTPalpha that is likely to be important for dynamic alterations in intra- and/or intermolecular interactions that are critical for RPTPalpha function.
Sonnenburg
Erica Dutil
ED
Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
Bilwes
Alexandrine
A
Hunter
Tony
T
Noel
Joseph P
JP
D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D017931:DNA Primers / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D019000:Phosphotyrosine; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry* / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000737:chemistry / Q000378:metabolism; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D018909:src Homology Domains
D017931:DNA Primers; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D019000:Phosphotyrosine; D016392:Proto-Oncogene Proteins pp60(c-src); D017027:Protein Tyrosine Phosphatases; C516843:Ptpra protein, mouse; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4