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The GTPase-activating protein p120RasGAP has an evolutionarily conserved "FLVR-unique" SH2 domain.
- Source :
-
Journal of Biological Chemistry . 7/31/2020, Vol. 295 Issue 31, p10511-10521. 20p. - Publication Year :
- 2020
-
Abstract
- 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 p120Ras-GAP (RASA1) in its apo and peptide-bound form. We find that the arginine residue in the FLVR motif does not directly contact pTyr1087 of a bound phosphopeptide derived from p190Rho-GAP; 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." [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219258
- Volume :
- 295
- Issue :
- 31
- Database :
- Academic Search Index
- Journal :
- Journal of Biological Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 145246953
- Full Text :
- https://doi.org/10.1074/jbc.RA120.013976