IQGAP1 Is a Phosphotyrosine-Regulated Scaffold for SH2-Containing Proteins
The scaffold protein IQGAP1 associates with over 150 interactors to influence multiple biological processes. The molecular mechanisms that underly spatial and temporal regulation of these interactions, which are crucial for proper cell functions, remain poorly understood. The receptor tyrosine kinas...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-02-01
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| Series: | Cells |
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| Online Access: | https://www.mdpi.com/2073-4409/12/3/483 |
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| author | Louise Thines Zhigang Li David B. Sacks |
| author_facet | Louise Thines Zhigang Li David B. Sacks |
| author_sort | Louise Thines |
| collection | DOAJ |
| description | The scaffold protein IQGAP1 associates with over 150 interactors to influence multiple biological processes. The molecular mechanisms that underly spatial and temporal regulation of these interactions, which are crucial for proper cell functions, remain poorly understood. The receptor tyrosine kinase MET phosphorylates IQGAP1 on Tyr<sup>1510</sup>. Separately, Src homology 2 (SH2) domains mediate protein–protein interactions by binding specific phosphotyrosine residues. Here, we investigate whether MET-catalyzed phosphorylation of Tyr<sup>1510</sup> of IQGAP1 regulates the docking of SH2-containing proteins. Using a peptide array, we identified SH2 domains from several proteins, including the non-receptor tyrosine kinases Abl1 and Abl2, that bind to the Tyr<sup>1510</sup> of IQGAP1 in a phosphorylation-dependent manner. Using pure proteins, we validated that full-length Abl1 and Abl2 bind directly to phosphorylated Tyr<sup>1510</sup> of IQGAP1. In cells, MET inhibition decreases endogenous IQGAP1 phosphorylation and interaction with endogenous Abl1 and Abl2, indicating that binding is regulated by MET-catalyzed phosphorylation of IQGAP1. Functionally, IQGAP1 modulates basal and HGF-stimulated Abl signaling. Moreover, IQGAP1 binds directly to MET, inhibiting its activation and signaling. Collectively, our study demonstrates that IQGAP1 is a phosphotyrosine-regulated scaffold for SH2-containing proteins, thereby uncovering a previously unidentified mechanism by which IQGAP1 coordinates intracellular signaling. |
| first_indexed | 2024-03-11T09:49:40Z |
| format | Article |
| id | doaj.art-f76b8d9325364d5c8866bf29fab0a181 |
| institution | Directory Open Access Journal |
| issn | 2073-4409 |
| language | English |
| last_indexed | 2024-03-11T09:49:40Z |
| publishDate | 2023-02-01 |
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| record_format | Article |
| series | Cells |
| spelling | doaj.art-f76b8d9325364d5c8866bf29fab0a1812023-11-16T16:22:18ZengMDPI AGCells2073-44092023-02-0112348310.3390/cells12030483IQGAP1 Is a Phosphotyrosine-Regulated Scaffold for SH2-Containing ProteinsLouise Thines0Zhigang Li1David B. Sacks2Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892, USADepartment of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892, USADepartment of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892, USAThe scaffold protein IQGAP1 associates with over 150 interactors to influence multiple biological processes. The molecular mechanisms that underly spatial and temporal regulation of these interactions, which are crucial for proper cell functions, remain poorly understood. The receptor tyrosine kinase MET phosphorylates IQGAP1 on Tyr<sup>1510</sup>. Separately, Src homology 2 (SH2) domains mediate protein–protein interactions by binding specific phosphotyrosine residues. Here, we investigate whether MET-catalyzed phosphorylation of Tyr<sup>1510</sup> of IQGAP1 regulates the docking of SH2-containing proteins. Using a peptide array, we identified SH2 domains from several proteins, including the non-receptor tyrosine kinases Abl1 and Abl2, that bind to the Tyr<sup>1510</sup> of IQGAP1 in a phosphorylation-dependent manner. Using pure proteins, we validated that full-length Abl1 and Abl2 bind directly to phosphorylated Tyr<sup>1510</sup> of IQGAP1. In cells, MET inhibition decreases endogenous IQGAP1 phosphorylation and interaction with endogenous Abl1 and Abl2, indicating that binding is regulated by MET-catalyzed phosphorylation of IQGAP1. Functionally, IQGAP1 modulates basal and HGF-stimulated Abl signaling. Moreover, IQGAP1 binds directly to MET, inhibiting its activation and signaling. Collectively, our study demonstrates that IQGAP1 is a phosphotyrosine-regulated scaffold for SH2-containing proteins, thereby uncovering a previously unidentified mechanism by which IQGAP1 coordinates intracellular signaling.https://www.mdpi.com/2073-4409/12/3/483AblIQGAP1METphosphorylationphosphotyrosinereceptor tyrosine kinase |
| spellingShingle | Louise Thines Zhigang Li David B. Sacks IQGAP1 Is a Phosphotyrosine-Regulated Scaffold for SH2-Containing Proteins Cells Abl IQGAP1 MET phosphorylation phosphotyrosine receptor tyrosine kinase |
| title | IQGAP1 Is a Phosphotyrosine-Regulated Scaffold for SH2-Containing Proteins |
| title_full | IQGAP1 Is a Phosphotyrosine-Regulated Scaffold for SH2-Containing Proteins |
| title_fullStr | IQGAP1 Is a Phosphotyrosine-Regulated Scaffold for SH2-Containing Proteins |
| title_full_unstemmed | IQGAP1 Is a Phosphotyrosine-Regulated Scaffold for SH2-Containing Proteins |
| title_short | IQGAP1 Is a Phosphotyrosine-Regulated Scaffold for SH2-Containing Proteins |
| title_sort | iqgap1 is a phosphotyrosine regulated scaffold for sh2 containing proteins |
| topic | Abl IQGAP1 MET phosphorylation phosphotyrosine receptor tyrosine kinase |
| url | https://www.mdpi.com/2073-4409/12/3/483 |
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