Allostery mediates ligand binding to Grb2 adaptor in a mutually exclusive manner

McDonald, Caleb B.; Hokayem, Jimmy El; Zafar, Nawal; Balke, Jordan E.; Bhat, Vikas; Mikles, David C.; Deegan, Brian J.; Seldeen, Kenneth L.; Farooq, Amjad

doi:10.1002/jmr.2256

Cited by 9 publications

(10 citation statements)

References 73 publications

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“…On the contrary of what previously observed for PDZ domains 27 , the calculated values reported in Table 1 do not show a clear prevalence of positive ΔΔΔG values. We speculate that this arises from the complex role of the C-SH3 domain, which is involved in several cellular pathways and has been suggested to interact with different ligands 31–33 .…”

Section: Resultsmentioning

confidence: 96%

Mapping the allosteric network within a SH3 domain

Malagrinò

Troilo

Bonetti

et al. 2019

Sci Rep

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SH3 domains are very abundant protein-protein interactions modules, involved in the regulation of several cellular processes. Whilst they have been associated to allosteric communication pathways between contiguous domains in multi-domain proteins, there is lack of information regarding the intra-domain allosteric cross-talk within the SH3 moiety. Here we scrutinize the presence of an allosteric network in the C-terminal SH3 domain of Grb2 protein, upon binding the Grb2-associated binding 2 protein. To explore allostery, we performed double mutant cycle analysis, a powerful quantitative approach based on mutagenesis in conjunction with kinetic experiments. Data reveal the presence of an unexpected allosteric sparse network that modulates the affinity between the SH3 domain and its physiological partner.

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Section: Resultsmentioning

confidence: 96%

Mapping the allosteric network within a SH3 domain

Malagrinò

Troilo

Bonetti

et al. 2019

Sci Rep

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“…Therefore, increased Sos1 protein abundance might not only determine RasGEF usage, but may also be required to promote sufficient LAT oligomerization to stimulate proliferative responses at this stage. In addition to Sos1, c-Cbl (11) and Gab1 (23) can form 1:2 complexes with Grb2 and therefore have the potential to promote Grb2-dependent LAT oligomerization. It will be interesting to examine whether, similar to what is seen for the RasGEF activities of Sos1 versus RasGRP1, different scaffolds are differentially regulated to promote LAT oligomerization at different stages of T cell development.…”

Section: Discussionmentioning

confidence: 99%

The Ability of Sos1 to Oligomerize the Adaptor Protein LAT Is Separable from Its Guanine Nucleotide Exchange Activity in Vivo

et al. 2013

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The activation of the small guanosine triphosphatase Ras by the guanine nucleotide exchange factor (GEF) Sos1 (Son of Sevenless 1) is a central feature of many receptor-stimulated signaling pathways. In developing T cells (thymocytes), Sos1-dependent activation of extracellular signal–regulated kinase (ERK) is required to stimulate cellular proliferation and differentiation. Here, we showed that in addition to its GEF activity, Sos1 acted as a scaffold to nucleate oligomerization of the T cell adaptor protein LAT (linker for activation of T cells) in vivo. The scaffold function of Sos1 depended on its ability to binding to the adaptor protein Grb2. Furthermore, the GEF activity of Sos1 and the Sos1-dependent oligomerization of LAT were separable functions in vivo. Whereas the GEF activity of Sos1 was required for optimal ERK phosphorylation in response to T cell receptor (TCR) stimulation, the Sos1-dependent oligomerization of LAT was required for maximal TCR-dependent phosphorylation and activation of phospholipase C γ1 and Ca2+ signaling. Finally, both of these Sos1 functions were required for early thymocyte proliferation. Whereas transgenic restoration of either the GEF activity or LAT-oligomerization functions of Sos1 alone failed to rescue thymocyte development in Sos1-deficient mice, simultaneous reconstitution of these two signals in the same cell restored normal T cell development. This ability of Sos1 to act both as a RasGEF and as a scaffold to nucleate Grb2-dependent adaptor oligomerization may also occur in other Grb2-dependent pathways, such as those activated by growth factor receptors.

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“…Within the FAK-bound molecule of Grb2, the occupancies of the Grb2 N-and C-SH3 domains are not known. Occupancy of one Grb2 SH3 domain sterically hinders ligand binding to the other, such that the C-SH3 and the N-SH3 domains are not simultaneously engaged (55). Also, all known Grb2 dimer-protein complexes use either both C-SH3 domains or both N-SH3 domains of the dimer to mediate protein binding, as found not only with the Grb2-FGFR2 receptor complex (53) but also with Grb2-Sos (both N-SH3) or Grb2-Gab1 (both C-SH3 domains) complexes that form in a 2:1 stoichiometry (55).…”

mentioning

confidence: 99%

Grb2 Promotes Integrin-Induced Focal Adhesion Kinase (FAK) Autophosphorylation and Directs the Phosphorylation of Protein Tyrosine Phosphatase α by the Src-FAK Kinase Complex

Cheng

Sun

Schlaepfer

et al. 2014

Molecular and Cellular Biology

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eThe integrin-activated Src-focal adhesion kinase (FAK) kinase complex phosphorylates PTP␣ at Tyr789, initiating PTP␣-mediated signaling that promotes cell migration. Recruitment of the BCAR3-Cas complex by PTP␣-phospho-Tyr789 at focal adhesions is one mechanism of PTP␣ signaling. The adaptor protein Grb2 is also recruited by PTP␣-phospho-Tyr789, although the role of the PTP␣-Grb2 complex in integrin signaling is unknown. We show that silencing Grb2 expression in fibroblasts abolishes PTP␣-Tyr789 phosphorylation and that this is due to two unexpected actions of Grb2. First, Grb2 promotes integrin-induced autophosphorylation of FAK-Tyr397. This is impaired in Grb2-depleted cells and prohibits FAK activation and formation of the Src-FAK complex. Grb2-depleted cells contain less paxillin, and paxillin overexpression rescues FAK-Tyr397 phosphorylation, suggesting that the FAK-activating action of Grb2 involves paxillin. A second distinct role for Grb2 in PTP␣-Tyr789 phosphorylation involves Grb2-mediated coupling of Src-FAK and PTP␣. This requires two phosphosites, FAK-Tyr925 and PTP␣-Tyr789, for Grb2-Src homology 2 (SH2) binding. We propose that a Grb2 dimer links FAK and PTP␣, and this positions active Src-FAK in proximity with other, perhaps integrin-clustered, molecules of PTP␣ to enable maximal PTP␣-Tyr789 phosphorylation. These findings identify Grb2 as a new FAK activator and reveal its essential role in coordinating PTP␣ tyrosine phosphorylation to enable downstream integrin signaling and migration.

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Allostery mediates ligand binding to Grb2 adaptor in a mutually exclusive manner

Cited by 9 publications

References 73 publications

Mapping the allosteric network within a SH3 domain

Mapping the allosteric network within a SH3 domain

The Ability of Sos1 to Oligomerize the Adaptor Protein LAT Is Separable from Its Guanine Nucleotide Exchange Activity in Vivo

Grb2 Promotes Integrin-Induced Focal Adhesion Kinase (FAK) Autophosphorylation and Directs the Phosphorylation of Protein Tyrosine Phosphatase α by the Src-FAK Kinase Complex

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