The GTPase-activating protein p120RasGAP has an evolutionarily conserved 'FLVR-unique' SH2 domain
| Autor: | Titus J. Boggon, Amy L. Stiegler, Rachel Jaber Chehayeb, Jessica Wang |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
030102 biochemistry & molecular biology GTPase-activating protein Chemistry Phosphopeptide Stereochemistry p120 GTPase Activating Protein Isothermal titration calorimetry Cell Biology Crystallography X-Ray SH2 domain Biochemistry Homology (biology) Protein–protein interaction Evolution Molecular src Homology Domains 03 medical and health sciences 030104 developmental biology Protein structure Humans Editors' Picks Molecular Biology Proto-oncogene tyrosine-protein kinase Src |
| Zdroj: | J Biol Chem |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.ra120.013976 |
| Popis: | The Src homology 2 (SH2) domain has a highly conserved architecture that recognizes linear phosphotyrosine motifs and is present in a wide range of signaling pathways across different evolutionary taxa. A hallmark of SH2 domains is the arginine residue in the conserved FLVR motif that forms a direct salt bridge with bound phosphotyrosine. Here, we solve the X-ray crystal structures of the C-terminal SH2 domain of p120RasGAP (RASA1) in its apo and peptide-bound form. We find that the arginine residue in the FLVR motif does not directly contact pTyr(1087) of a bound phosphopeptide derived from p190RhoGAP; rather, it makes an intramolecular salt bridge to an aspartic acid. Unexpectedly, coordination of phosphotyrosine is achieved by a modified binding pocket that appears early in evolution. Using isothermal titration calorimetry, we find that substitution of the FLVR arginine R377A does not cause a significant loss of phosphopeptide binding, but rather a tandem substitution of R398A (SH2 position βD4) and K400A (SH2 position βD6) is required to disrupt the binding. These results indicate a hitherto unrecognized diversity in SH2 domain interactions with phosphotyrosine and classify the C-terminal SH2 domain of p120RasGAP as “FLVR-unique.” |
| Databáze: | OpenAIRE |
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