scholarly journals Mutagenic analysis of the roles of SH2 and SH3 domains in regulation of the Abl tyrosine kinase.

1994 ◽  
Vol 14 (5) ◽  
pp. 2883-2894 ◽  
Author(s):  
B J Mayer ◽  
D Baltimore

We have used in vitro mutagenesis to examine in detail the roles of two modular protein domains, SH2 and SH3, in the regulation of the Abl tyrosine kinase. As previously shown, the SH3 domain suppresses an intrinsic transforming activity of the normally nontransforming c-Abl product in vivo. We show here that this inhibitory activity is extremely position sensitive, because mutants in which the position of the SH3 domain within the protein is subtly altered are fully transforming. In contrast to the case in vivo, the SH3 domain has no effect on the in vitro kinase activity of the purified protein. These results are consistent with a model in which the SH3 domain binds a cellular inhibitory factor, which in turn must physically interact with other parts of the kinase. Unlike the SH3 domain, the SH2 domain is required for transforming activity of activated Abl alleles. We demonstrate that SH2 domains from other proteins (Ras-GTPase-activating protein, Src, p85 phosphatidylinositol 3-kinase subunit, and Crk) can complement the absence of the Abl SH2 domain and that mutants with heterologous SH2 domains induce altered patterns of tyrosine-phosphorylated proteins in vivo. The positive function of the SH2 domain is relatively position independent, and the effect of multiple SH2 domains appears to be additive. These results suggest a novel mechanism for regulation of tyrosine kinases in which the SH2 domain binds to, and thereby enhances the phosphorylation of, a subset of proteins phosphorylated by the catalytic domain. Our data also suggest that the roles of the SH2 and SH3 domains in the regulation of Abl are different in several respects from the roles proposed for these domains in the closely related Src family of tyrosine kinases.

1994 ◽  
Vol 14 (5) ◽  
pp. 2883-2894
Author(s):  
B J Mayer ◽  
D Baltimore

We have used in vitro mutagenesis to examine in detail the roles of two modular protein domains, SH2 and SH3, in the regulation of the Abl tyrosine kinase. As previously shown, the SH3 domain suppresses an intrinsic transforming activity of the normally nontransforming c-Abl product in vivo. We show here that this inhibitory activity is extremely position sensitive, because mutants in which the position of the SH3 domain within the protein is subtly altered are fully transforming. In contrast to the case in vivo, the SH3 domain has no effect on the in vitro kinase activity of the purified protein. These results are consistent with a model in which the SH3 domain binds a cellular inhibitory factor, which in turn must physically interact with other parts of the kinase. Unlike the SH3 domain, the SH2 domain is required for transforming activity of activated Abl alleles. We demonstrate that SH2 domains from other proteins (Ras-GTPase-activating protein, Src, p85 phosphatidylinositol 3-kinase subunit, and Crk) can complement the absence of the Abl SH2 domain and that mutants with heterologous SH2 domains induce altered patterns of tyrosine-phosphorylated proteins in vivo. The positive function of the SH2 domain is relatively position independent, and the effect of multiple SH2 domains appears to be additive. These results suggest a novel mechanism for regulation of tyrosine kinases in which the SH2 domain binds to, and thereby enhances the phosphorylation of, a subset of proteins phosphorylated by the catalytic domain. Our data also suggest that the roles of the SH2 and SH3 domains in the regulation of Abl are different in several respects from the roles proposed for these domains in the closely related Src family of tyrosine kinases.


1992 ◽  
Vol 12 (2) ◽  
pp. 609-618
Author(s):  
B J Mayer ◽  
P K Jackson ◽  
R A Van Etten ◽  
D Baltimore

We have constructed a series of point mutations in the highly conserved FLVRES motif of the src homology 2 (SH2) domain of the abl tyrosine kinase. Mutant SH2 domains were expressed in bacteria, and their ability to bind to tyrosine-phosphorylated proteins was examined in vitro. Three mutants were greatly reduced in their ability to bind both phosphotyrosine itself and tyrosine-phosphorylated cellular proteins. All of the mutants that retained activity bound to the same set of tyrosine-phosphorylated proteins as did the wild type, suggesting that binding specificity was unaffected. These results implicate the FLVRES motif in direct binding to phosphotyrosine. When the mutant SH2 domains were inserted into an activated abl kinase and expressed in murine fibroblasts, decreased in vitro phosphotyrosine binding correlated with decreased transforming ability. This finding implies that SH2-phosphotyrosine interactions are involved in transmission of positive growth signals by the nonreceptor tyrosine kinases, most likely via the assembly of multiprotein complexes with other tyrosine-phosphorylated proteins.


1992 ◽  
Vol 12 (2) ◽  
pp. 609-618 ◽  
Author(s):  
B J Mayer ◽  
P K Jackson ◽  
R A Van Etten ◽  
D Baltimore

We have constructed a series of point mutations in the highly conserved FLVRES motif of the src homology 2 (SH2) domain of the abl tyrosine kinase. Mutant SH2 domains were expressed in bacteria, and their ability to bind to tyrosine-phosphorylated proteins was examined in vitro. Three mutants were greatly reduced in their ability to bind both phosphotyrosine itself and tyrosine-phosphorylated cellular proteins. All of the mutants that retained activity bound to the same set of tyrosine-phosphorylated proteins as did the wild type, suggesting that binding specificity was unaffected. These results implicate the FLVRES motif in direct binding to phosphotyrosine. When the mutant SH2 domains were inserted into an activated abl kinase and expressed in murine fibroblasts, decreased in vitro phosphotyrosine binding correlated with decreased transforming ability. This finding implies that SH2-phosphotyrosine interactions are involved in transmission of positive growth signals by the nonreceptor tyrosine kinases, most likely via the assembly of multiprotein complexes with other tyrosine-phosphorylated proteins.


1993 ◽  
Vol 13 (9) ◽  
pp. 5225-5232 ◽  
Author(s):  
X Liu ◽  
L E Marengere ◽  
C A Koch ◽  
T Pawson

Fibroblasts transformed by v-src or by related oncogenes encoding activated tyrosine kinases contain elevated levels of polyphosphoinositides with phosphate at the D-3 position of the inositol ring, as a result of the activation of phosphatidylinositol (PI) 3'-kinase. v-src-transformed cells also contain increased levels of PI 3'-kinase activity immunoprecipitable with anti-phosphotyrosine antibodies; furthermore, PI 3'-kinase can be detected in association with the v-Src tyrosine kinase. To identify regions of v-Src that can interact with PI 3'-kinase, the v-Src SH2 and SH3 domains were expressed in bacteria and incubated with lysates of normal chicken embryo fibroblasts. In vitro, the v-Src SH3 domain, but not the SH2 domain, bound PI 3'-kinase in lysates of uninfected chicken embryo fibroblasts. Substitutions of two highly conserved SH3 residues implicated in ligand binding abolished the ability of the v-Src SH3 domain to associate with PI 3'-kinase. Furthermore, the v-Src SH3 domain bound in vitro to the amino-terminal region of the p85 alpha subunit of PI 3'-kinase. These results suggest that the v-Src SH3 domain may mediate an interaction between the v-Src tyrosine kinase and PI 3'-kinase, by direct binding to p85.


1995 ◽  
Vol 15 (1) ◽  
pp. 186-197 ◽  
Author(s):  
S Richard ◽  
D Yu ◽  
K J Blumer ◽  
D Hausladen ◽  
M W Olszowy ◽  
...  

src family tyrosine kinases contain two noncatalytic domains termed src homology 3 (SH3) and SH2 domains. Although several other signal transduction molecules also contain tandemly occurring SH3 and SH2 domains, the function of these closely spaced domains is not well understood. To identify the role of the SH3 domains of src family tyrosine kinases, we sought to identify proteins that interacted with this domain. By using the yeast two-hybrid system, we identified p62, a tyrosine-phosphorylated protein that associates with p21ras GTPase-activating protein, as a src family kinase SH3-domain-binding protein. Reconstitution of complexes containing p62 and the src family kinase p59fyn in HeLa cells demonstrated that complex formation resulted in tyrosine phosphorylation of p62 and was mediated by both the SH3 and SH2 domains of p59fyn. The phosphorylation of p62 by p59fyn required an intact SH3 domain, demonstrating that one function of the src family kinase SH3 domains is to bind and present certain substrates to the kinase. As p62 contains at least five SH3-domain-binding motifs and multiple tyrosine phosphorylation sites, p62 may interact with other signalling molecules via SH3 and SH2 domain interactions. Here we show that the SH3 and/or SH2 domains of the signalling proteins Grb2 and phospholipase C gamma-1 can interact with p62 both in vitro and in vivo. Thus, we propose that one function of the tandemly occurring SH3 and SH2 domains of src family kinases is to bind p62, a multifunctional SH3 and SH2 domain adapter protein, linking src family kinases to downstream effector and regulatory molecules.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2628-2628
Author(s):  
Lauren M Brown ◽  
Hannah Huckstep ◽  
Jarrod Sandow ◽  
Ray C Bartolo ◽  
Nadia Davidson ◽  
...  

Abstract Background: Philadelphia-like acute lymphoblastic leukaemia (Ph-like ALL) is a high-risk subtype of ALL driven by a range of tyrosine kinase and cytokine receptor rearrangements. ABL1-class rearrangements (ABL1, ABL2, CSF1R and PDGFRB) account for 17% of Ph-like ALL cases in children, and are clinically important to identify as they can be therapeutically targeted with tyrosine kinase inhibitors (TKIs). While the p190 BCR-ABL1 fusion is well described, less is known about the function and downstream signalling by rare ABL1 fusions. We identified a rare ABL1 fusion, SFPQ-ABL1, in a paediatric B-ALL patient using RNA-sequencing. This fusion lacks the ABL1 Src-homology-3 (SH3) and part of the SH2 domain, which are retained in BCR-ABL1. Other ABL1 fusions, RCSD1-ABL1 and SNX2-ABL1, have a similar structure. In this work we have utilised phosphoproteomics and Stable Isotope Labelling by Amino Acids in Cell Culture (SILAC), as well as in vitro and in vivo models, to determine differential signalling pathways between SFPQ-ABL1 and BCR-ABL1. Methods: We cloned SFPQ-ABL1 from patient cDNA, and engineered SFPQ-ABL1 and BCR-ABL1 fusions to include or delete the SH2 and SH3 domains. We performed proliferation and viability assays to assess the ability of these fusions to transform Ba/F3 cells and test sensitivity to TKIs. We performed total phosphopeptide and phosphotyrosine enrichments and utilised mass spectrometry to identify the phosphoproteome activated by canonical SFPQ-ABL1 and BCR-ABL1. Over representation analysis was performed on phosphopeptides significantly differing between BCR-ABL and SFPQ-ABL (Log fold change cut-off > 2.5) using the Gene Ontology (GO) knowledge base under the biological process category. Furthermore, we compared the phosphoproteome of canonical SFPQ-ABL1 to SFPQ-ABL1 with the SH2 and SH3 domains reintroduced (SFPQ-ABL1+SH). We have also developed novel mouse models, using syngeneic transplantation, of SFPQ-ABL1 and SNX2-ABL1 driven leukaemia. Results: SFPQ-ABL1 expressing Ba/F3 cells are sensitive to cell death induced by TKIs that block ABL1. Interestingly, while SFPQ-ABL1 and BCR-ABL1 both effectively blocked apoptosis, SFPQ-ABL1 was less able to drive cytokine-independent proliferation. Phosphoproteomic analysis showed that BCR-ABL1 and SFPQ-ABL1 differentially activate downstream signalling pathways, including SH-binding proteins. Hierarchical clustering of phosphopeptides quantified from cells expressing canonical BCR-ABL1, SFPQ-ABL1, and SFPQ-ABL1+SH, demonstrated that BCR-ABL1 and SFPQ-ABL1+SH were more similar to each other than to SFPQ-ABL1. SFPQ-ABL1 expression resulted in phosphorylation of proteins involved in RNA processing, metabolism and splicing, suggesting that SFPQ region of SFPQ-ABL1 also contributes to signalling. Conclusions: In this study, we have utilised phosphoproteomics for the unbiased identification of signalling nodes that are required for the function of different classes of ABL fusions. We have developed novel in vitro and in vivo models to further understand how these fusions function to drive leukaemia. Our data also suggests that ABL1 fusion partners play a role beyond dimerization and transphosphorylation of the kinase domains in oncogenic signalling, but further study is needed to establish the contribution to leukaemogenesis. Establishing signalling pathways that are critical to the function of rare ABL1 fusions may inform clinical approaches to treating this disease. Disclosures No relevant conflicts of interest to declare.


1994 ◽  
Vol 14 (3) ◽  
pp. 1680-1688
Author(s):  
M D Schaller ◽  
J D Hildebrand ◽  
J D Shannon ◽  
J W Fox ◽  
R R Vines ◽  
...  

The phosphorylation of protein tyrosine kinases (PTKs) on tyrosine residues is a critical regulatory event that modulates catalytic activity and triggers the physical association of PTKs with Src homology 2 (SH2)-containing proteins. The integrin-linked focal adhesion kinase, pp125FAK, exhibits extracellular matrix-dependent phosphorylation on tyrosine and physically associates with two nonreceptor PTKs, pp60src and pp59fyn, via their SH2 domains. Herein, we identify Tyr-397 as the major site of tyrosine phosphorylation on pp125FAK both in vivo and in vitro. Tyrosine 397 is located at the juncture of the N-terminal and catalytic domains, a novel site for PTK autophosphorylation. Mutation of Tyr-397 to a nonphosphorylatable residue dramatically impairs the phosphorylation of pp125FAK on tyrosine in vivo and in vitro. The mutation of Tyr-397 to Phe also inhibits the formation of stable complexes with pp60src in cells expressing Src and FAK397F, suggesting that autophosphorylation of pp125FAK may regulate the association of pp125FAK with Src family kinases in vivo. The identification of Tyr-397 as a major site for FAK autophosphorylation provides one of the first examples of a cellular protein containing a high-affinity binding site for a Src family kinase SH2 domain. This finding has implications for models describing the mechanisms of action of pp125FAK, the regulation of the Src family of PTKs, and signal transduction through the integrins.


1993 ◽  
Vol 13 (9) ◽  
pp. 5225-5232
Author(s):  
X Liu ◽  
L E Marengere ◽  
C A Koch ◽  
T Pawson

Fibroblasts transformed by v-src or by related oncogenes encoding activated tyrosine kinases contain elevated levels of polyphosphoinositides with phosphate at the D-3 position of the inositol ring, as a result of the activation of phosphatidylinositol (PI) 3'-kinase. v-src-transformed cells also contain increased levels of PI 3'-kinase activity immunoprecipitable with anti-phosphotyrosine antibodies; furthermore, PI 3'-kinase can be detected in association with the v-Src tyrosine kinase. To identify regions of v-Src that can interact with PI 3'-kinase, the v-Src SH2 and SH3 domains were expressed in bacteria and incubated with lysates of normal chicken embryo fibroblasts. In vitro, the v-Src SH3 domain, but not the SH2 domain, bound PI 3'-kinase in lysates of uninfected chicken embryo fibroblasts. Substitutions of two highly conserved SH3 residues implicated in ligand binding abolished the ability of the v-Src SH3 domain to associate with PI 3'-kinase. Furthermore, the v-Src SH3 domain bound in vitro to the amino-terminal region of the p85 alpha subunit of PI 3'-kinase. These results suggest that the v-Src SH3 domain may mediate an interaction between the v-Src tyrosine kinase and PI 3'-kinase, by direct binding to p85.


1992 ◽  
Vol 12 (3) ◽  
pp. 1366-1374 ◽  
Author(s):  
C A Koch ◽  
M F Moran ◽  
D Anderson ◽  
X Q Liu ◽  
G Mbamalu ◽  
...  

The Src homology 2 (SH2) domain is a noncatalytic region which is conserved among a number of signaling and transforming proteins, including cytoplasmic protein-tyrosine kinases and Ras GTPase-activating protein (GAP). Genetic and biochemical data indicate that the SH2 domain of the p60v-src (v-Src) protein-tyrosine kinase is required for full v-src transforming activity and may direct the association of v-Src with specific tyrosine-phosphorylated proteins. To test the ability of the v-Src SH2 domain to mediate protein-protein interactions, v-Src polypeptides were expressed as fusion proteins in Escherichia coli. The bacterial v-Src SH2 domain bound a series of tyrosine-phosphorylated proteins in a lysate of v-src-transformed Rat-2 cells, including prominent species of 130 and 62 kDa (p130 and p62). The p130 and p62 tyrosine-phosphorylated proteins that complexed v-Src SH2 in vitro also associated with v-Src in v-src-transformed Rat-2 cells; this in vivo binding was dependent on the v-Src SH2 domain. In addition to binding soluble p62 and p130, the SH2 domains of v-Src, GAP, and v-Crk directly recognized these phosphotyrosine-containing proteins which had been previously denatured and immobilized on a filter. In addition, the SH2 domains of GAP and v-Crk bound to the GAP-associated protein p190 immobilized on a nitrocellulose membrane. These results show that SH2 domains bind directly to tyrosine-phosphorylated proteins and that the Src SH2 domain can bind phosphorylated targets of the v-Src kinase domain.(ABSTRACT TRUNCATED AT 250 WORDS)


1996 ◽  
Vol 16 (12) ◽  
pp. 6985-6992 ◽  
Author(s):  
H Jiao ◽  
K Berrada ◽  
W Yang ◽  
M Tabrizi ◽  
L C Platanias ◽  
...  

SHP-1 is an SH2-containing cytoplasmic tyrosine phosphatase that is widely distributed in cells of the hematopoietic system. SHP-1 plays an important role in the signal transduction of many cytokine receptors, including the receptor for erythropoietin, by associating via its SH2 domains to the receptors and dephosphorylating key substrates. Recent studies have suggested that SHP-1 regulates the function of Jak family tyrosine kinases, as shown by its constitutive association with the Tyk2 kinase and the hyperphosphorylation of Jak kinases in the motheaten cells that lack functional SHP-1. We have examined the interactions of SHP-1 with two tyrosine kinases activated during engagement of the erythropoietin receptor, the Janus family kinase Jak-2 and the c-fps/fes kinase. Immunoblotting studies with extracts from mouse hematopoietic cells demonstrated that Jak2, but not c-fes, was present in anti-SHP-1 immunoprecipitates, suggesting that SHP-1 selectively associates with Jak2 in vivo. Consistent with this, when SHP-1 was coexpressed with these kinases in Cos-7 cells, it associated with and dephosphorylated Jak2 but not c-fes. Transient cotransfection of truncated forms of SHP-1 with Jak2 demonstrated that the SHP-1-Jak2 interaction is direct and is mediated by a novel binding activity present in the N terminus of SHP-1, independently of SH2 domain-phosphotyrosine interaction. Such SHP-1-Jak2 interaction resulted in induction of the enzymatic activity of the phosphatase in in vitro protein tyrosine phosphatase assays. Interestingly, association of the SH2n domain of SHP-1 with the tyrosine phosphorylated erythropoietin receptor modestly potentiated but was not essential for SHP-1-mediated dephosphorylation of Jak2 and had no effect on c-fes phosphorylation. These data indicate that the main mechanism for regulation of Jak2 phosphorylation by SHP-1 involves a direct, SH2-independent interaction with Jak2 and suggest the existence of similar mechanisms for other members of the Jak family of kinases. They also suggest that such interactions may provide one of the mechanisms that control SHP-1 substrate specificity.


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