scholarly journals Calcium Release at Fertilization in Starfish Eggs Is Mediated by Phospholipase Cγ

1997 ◽  
Vol 138 (6) ◽  
pp. 1303-1311 ◽  
Author(s):  
David J. Carroll ◽  
Chodavarapu S. Ramarao ◽  
Lisa M. Mehlmann ◽  
Serge Roche ◽  
Mark Terasaki ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Calcium Release ◽  
Specific Inhibitor ◽  
Sh2 Domain ◽  
High Concentration ◽  
Serotonin 2C Receptor ◽  
Sh2 Domains ◽  
Src Homology 2 ◽  
Src Homology ◽  
Domain Protein

Although inositol trisphosphate (IP3) functions in releasing Ca2+ in eggs at fertilization, it is not known how fertilization activates the phospholipase C that produces IP3. To distinguish between a role for PLCγ, which is activated when its two src homology-2 (SH2) domains bind to an activated tyrosine kinase, and PLCβ, which is activated by a G protein, we injected starfish eggs with a PLCγ SH2 domain fusion protein that inhibits activation of PLCγ. In these eggs, Ca2+ release at fertilization was delayed, or with a high concentration of protein and a low concentration of sperm, completely inhibited. The PLCγSH2 protein is a specific inhibitor of PLCγ in the egg, since it did not inhibit PLCβ activation of Ca2+ release initiated by the serotonin 2c receptor, or activation of Ca2+ release by IP3 injection. Furthermore, injection of a PLCγ SH2 domain protein mutated at its phosphotyrosine binding site, or the SH2 domains of another protein (the phosphatase SHP2), did not inhibit Ca2+ release at fertilization. These results indicate that during fertilization of starfish eggs, activation of phospholipase Cγ by an SH2 domain-mediated process stimulates the production of IP3 that causes intracellular Ca2+ release.

scholarly journals PLC-γ directly binds activated c-Src, which is necessary for carbachol-mediated inhibition of NHE3 activity in Caco-2/BBe cells

2013 ◽  
Vol 305 (3) ◽  
pp. C266-C275 ◽  
Author(s):  
Nicholas C. Zachos ◽  
Luke J. Lee ◽  
Olga Kovbasnjuk ◽  
Xuhang Li ◽  
Mark Donowitz
Keyword(s):  
Sh2 Domain ◽  
Signaling Proteins ◽  
Multiprotein Complexes ◽  
Sh2 Domains ◽  
Src Homology 2 ◽  
Src Inhibitor ◽  
Intracellular Ca ◽  
Direct Binding ◽  
Src Homology

Elevated levels of intracellular Ca2+([Ca2+]i) inhibit Na+/H+exchanger 3 (NHE3) activity in the intact intestine. We previously demonstrated that PLC-γ directly binds NHE3, an interaction that is necessary for [Ca2+]iinhibition of NHE3 activity, and that PLC-γ Src homology 2 (SH2) domains may scaffold Ca2+signaling proteins necessary for regulation of NHE3 activity. [Ca2+]iregulation of NHE3 activity is also c-Src dependent; however, the mechanism by which c-Src is involved is undetermined. We hypothesized that the SH2 domains of PLC-γ might link c-Src to NHE3-containing complexes to mediate [Ca2+]iinhibition of NHE3 activity. In Caco-2/BBe cells, carbachol (CCh) decreased NHE3 activity by ∼40%, an effect abolished with the c-Src inhibitor PP2. CCh treatment increased the amount of active c-Src as early as 1 min through increased Y416phosphorylation. Coimmunoprecipitation demonstrated that c-Src associated with PLC-γ, but not NHE3, under basal conditions, an interaction that increased rapidly after CCh treatment and occurred before the dissociation of PLC-γ and NHE3 that occurred 10 min after CCh treatment. Finally, direct binding to c-Src only occurred through the PLC-γ SH2 domains, an interaction that was prevented by blocking the PLC-γ SH2 domain. This study demonstrated that c-Src 1) activity is necessary for [Ca2+]iinhibition of NHE3 activity, 2) activation occurs rapidly (∼1 min) after CCh treatment, 3) directly binds PLC-γ SH2 domains and associates dynamically with PLC-γ under elevated [Ca2+]iconditions, and 4) does not directly bind NHE3. Under elevated [Ca2+]iconditions, PLC-γ scaffolds c-Src into NHE3-containing multiprotein complexes before dissociation of PLC-γ from NHE3 and subsequent endocytosis of NHE3.

Src Homology 2 Domain Binding as a Phosphoproteomic Approach to Signaling in Acute Lymphoblastic Leukemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4442-4442
Author(s):  
Martin A. Horstmann ◽  
Peter Nollau
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Lymphoblastic Leukemia ◽  
Adaptor Proteins ◽  
Sh2 Domain ◽  
Effector Proteins ◽  
Sh2 Domains ◽  
Binding Domains ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain

Abstract A general theme of orchestrated signal transduction is played by activated receptor phosphotyrosine kinases (PTK) and receptor PTK targets which propagate signals via recognition of sequence-specific phoshorylated tyrosines by so-called Src homology 2 (SH2) domains. SH2 domain interactions are used as a means of recruiting target proteins to activated PTKs and to translocate them to the plasma membrane where many effector proteins activated by receptor PTKs such as phospholipase C-γ or PI-3 kinase have their substrates. SH2 domains make up the most prevalent type of phosphotyrosine binding domains involved in signaling downstream of activated PTKs. SH2 domains are not only present in proteins with intrinsic enzymatic activity but also in adaptor proteins which shuttle effector enzymes to target signaling complexes. Increasing numbers of diseases are known to involve phosphotyrosine specific kinases and/or phosphatases going awry exemplified by the notorious ErbB2 receptor PTK in breast cancer or the Bcr-Abl PTK in CML. Currently, the tyrosine phosphorylation state in most acute lymphoblastic leukemias is undefined which is predicted to differ among the various subgroups and to be distinct from the signaling state of normal hematopoietic cells. To identify aberrant tyrosine kinase or phosphatase activity in the various types of acute lymphoblastic leukemia is of great interest since enzymes in general make good targets for drugs. A novel SH2 domain binding approach is presented which can detect distinctive profiles of tyrosine-phosphorylated proteins in complex mixtures of cellular proteins. A battery of SH2 domains is employed as probes in a competitive far-Western blot based assay to identify specific tyrosine-phosphorylated sites which reflect active signaling pathways in a cell. A further refinement of this technology is under way with DNA-tagged probes being developed which allow for multiplexing and high throughput quantitative assessment of SH2-domain binding by quantitative PCR or microarray technologies.

scholarly journals A region of the 85-kilodalton (kDa) subunit of phosphatidylinositol 3-kinase binds the 110-kDa catalytic subunit in vivo.

1993 ◽  
Vol 13 (9) ◽  
pp. 5560-5566 ◽  
Author(s):  
A Klippel ◽  
J A Escobedo ◽  
Q Hu ◽  
L T Williams
Keyword(s):  
Growth Factor ◽  
Growth Factor Receptor ◽  
Sh2 Domain ◽  
Catalytic Subunit ◽  
Phosphatidylinositol 3 Kinase ◽  
Region Gene ◽  
Sh2 Domains ◽  
Src Homology 2 ◽  
Src Homology

Phosphatidylinositol (PI) 3-kinase is a heterodimer consisting of an 85-kDa subunit (p85) and 110-kDa subunit (p110). The 85-kDa noncatalytic subunit, which contains two Src homology 2 (SH2) domains, one SH3 domain, and a domain homologous to the carboxy terminus of the breakpoint cluster region gene product, is known to mediate the association of the PI 3-kinase complex with activated growth factor receptors. We previously demonstrated that the C-terminal SH2 domain of p85 is responsible for the interaction of PI 3-kinase with phosphorylated platelet-derived growth factor receptor. To define the region in p85 that directs the complex formation with the PI 3-kinase catalytic subunit, a series of truncated p85 mutants was analyzed for association with p110 in vivo. We found that a fragment of p85 containing the region between the two SH2 domains was sufficient to promote the interaction with p110 in vivo. The complex between the fragment of p85 and p110 had PI 3-kinase activity that was comparable in magnitude to the activity of p110 associated with full-length p85. The binding with p110 was abolished when this domain in p85 was disrupted. These results identify a novel structural and functional element that is responsible for localizing the catalytic subunit of PI 3-kinase.

scholarly journals Structural Implications of STAT3 and STAT5 SH2 Domain Mutations

Cancers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1757 ◽  
Author(s):  
Elvin D. de Araujo ◽  
Anna Orlova ◽  
Heidi A. Neubauer ◽  
Dávid Bajusz ◽  
Hyuk-Soo Seo ◽  
...  
Keyword(s):  
Structural Data ◽  
Sh2 Domain ◽  
Therapeutic Interventions ◽  
Nuclear Accumulation ◽  
Sequencing Analysis ◽  
Stat Proteins ◽  
Sh2 Domains ◽  
Src Homology 2 ◽  
Domain Interactions ◽  
Src Homology

Src Homology 2 (SH2) domains arose within metazoan signaling pathways and are involved in protein regulation of multiple pleiotropic cascades. In signal transducer and activator of transcription (STAT) proteins, SH2 domain interactions are critical for molecular activation and nuclear accumulation of phosphorylated STAT dimers to drive transcription. Sequencing analysis of patient samples has revealed the SH2 domain as a hotspot in the mutational landscape of STAT proteins although the functional impact for the vast majority of these mutations remains poorly characterized. Despite several well resolved structures for SH2 domain-containing proteins, structural data regarding the distinctive STAT-type SH2 domain is limited. Here, we review the unique features of STAT-type SH2 domains in the context of all currently reported STAT3 and STAT5 SH2 domain clinical mutations. The genetic volatility of specific regions in the SH2 domain can result in either activating or deactivating mutations at the same site in the domain, underscoring the delicate evolutionary balance of wild type STAT structural motifs in maintaining precise levels of cellular activity. Understanding the molecular and biophysical impact of these disease-associated mutations can uncover convergent mechanisms of action for mutations localized within the STAT SH2 domain to facilitate the development of targeted therapeutic interventions.

scholarly journals SH2 domain-mediated activation of an SRC family kinase is not required to initiate Ca2+ release at fertilization in mouse eggs

Reproduction ◽  
2005 ◽  
Vol 129 (5) ◽  
pp. 557-564 ◽  
Author(s):  
Lisa M Mehlmann ◽  
Laurinda A Jaffe
Keyword(s):  
Small Molecule ◽  
Sh2 Domain ◽  
Src Family Kinases ◽  
Dominant Negative ◽  
Sh2 Domains ◽  
Src Homology 2 ◽  
Src Homology ◽  
Mammalian Fertilization ◽  
Mammalian Eggs ◽  
Mouse Eggs

SRC family kinases (SFKs) function in initiating Ca2+release at fertilization in several species in the vertebrate evolutionary line, but whether they play a similar role in mammalian fertilization has been uncertain. We investigated this question by first determining which SFK proteins are expressed in mouse eggs, and then measuring Ca2+release at fertilization in the presence of dominant negative inhibitors. FYN and YES proteins were found in mouse eggs, but other SFKs were not detected; based on this, we injected mouse eggs with a mixture of FYN and YES Src homology 2 (SH2) domains. These SH2 domains were effective inhibitors of Ca2+release at fertilization in starfish eggs, but did not inhibit Ca2+release at fertilization in mouse eggs. Thus the mechanism by which sperm initiate Ca2+release in mouse eggs does not depend on SH2 domain-mediated activation of an SFK. We also tested the small molecule SFK inhibitor SU6656, and found that it became compartmentalized in the egg cytoplasm, thus suggesting caution in the use of this inhibitor. Our findings indicate that although the initiation of Ca2+release at fertilization of mammalian eggs occurs by a pathway that has many similarities to that in evolutionarily earlier animal groups, the requirement for SH2 domain-mediated activation of an SFK is not conserved.

A region of the 85-kilodalton (kDa) subunit of phosphatidylinositol 3-kinase binds the 110-kDa catalytic subunit in vivo

1993 ◽  
Vol 13 (9) ◽  
pp. 5560-5566
Author(s):  
A Klippel ◽  
J A Escobedo ◽  
Q Hu ◽  
L T Williams
Keyword(s):  
Growth Factor ◽  
Growth Factor Receptor ◽  
Sh2 Domain ◽  
Catalytic Subunit ◽  
Phosphatidylinositol 3 Kinase ◽  
Region Gene ◽  
Sh2 Domains ◽  
Src Homology 2 ◽  
Src Homology

Phosphatidylinositol (PI) 3-kinase is a heterodimer consisting of an 85-kDa subunit (p85) and 110-kDa subunit (p110). The 85-kDa noncatalytic subunit, which contains two Src homology 2 (SH2) domains, one SH3 domain, and a domain homologous to the carboxy terminus of the breakpoint cluster region gene product, is known to mediate the association of the PI 3-kinase complex with activated growth factor receptors. We previously demonstrated that the C-terminal SH2 domain of p85 is responsible for the interaction of PI 3-kinase with phosphorylated platelet-derived growth factor receptor. To define the region in p85 that directs the complex formation with the PI 3-kinase catalytic subunit, a series of truncated p85 mutants was analyzed for association with p110 in vivo. We found that a fragment of p85 containing the region between the two SH2 domains was sufficient to promote the interaction with p110 in vivo. The complex between the fragment of p85 and p110 had PI 3-kinase activity that was comparable in magnitude to the activity of p110 associated with full-length p85. The binding with p110 was abolished when this domain in p85 was disrupted. These results identify a novel structural and functional element that is responsible for localizing the catalytic subunit of PI 3-kinase.

SH2 domains: role, structure and implications for molecular medicine

2004 ◽  
Vol 6 (3) ◽  
pp. 1-18 ◽  
Author(s):  
Gabriel Waksman ◽  
Sangaralingam Kumaran ◽  
Olga Lubman
Keyword(s):  
Receptor Activation ◽  
Specific Protein ◽  
Sh2 Domain ◽  
Molecular Medicine ◽  
Protein Targets ◽  
Regulate Gene Expression ◽  
Sh2 Domains ◽  
Role Structure ◽  
Src Homology 2 ◽  
Src Homology

Src homology 2 (SH2) domains are protein modules (of ~100 amino acids) found in many proteins involved in tyrosine kinase signalling cascades. Their function is to bind tyrosine-phosphorylated sequences in specific protein targets. Binding of an SH2 domain to its cognate tyrosine-phosphorylated target links receptor activation to downstream signalling, both to the nucleus to regulate gene expression and throughout the cytoplasm of the cell. This review recapitulates the roles that SH2 domains play in normal and diseased states, describes the successes of SH2 domain research in deciphering their mechanism of action, and provides an overview of the use of SH2 domains as structural templates for the design of inhibitor drugs.

scholarly journals The Effect of Transient Global Ischemia on the Interaction of Src and Fyn with the N-Methyl-d-Aspartate Receptor and Postsynaptic Densities: Possible Involvement of Src Homology 2 Domains

1999 ◽  
Vol 19 (8) ◽  
pp. 880-888 ◽  
Author(s):  
Norio Takagi ◽  
Herman H. Cheung ◽  
Nankie Bissoon ◽  
Lucy Teves ◽  
M. Christopher Wallace ◽  
...  
Keyword(s):  
Nmda Receptor ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Phosphatase ◽  
Sh2 Domain ◽  
Signaling Proteins ◽  
Glutathione S Transferase ◽  
Nmda Receptor Subunits ◽  
Sh2 Domains ◽  
Src Homology 2 ◽  
Src Homology

Transient ischemia increases tyrosine phosphorylation of N-methyl-d-aspartate (NMDA) receptor subunits NR2A and NR2B in the rat hippocampus. The authors investigated the effects of this increase on the ability of the receptor subunits to bind to the Src homology 2 (SH2) domains of Src and Fyn expressed as glutathione-S-transferase–SH2 fusion proteins. The NR2A and NR2B bound to each of the SH2 domains and binding was increased approximately twofold after ischemia and reperfusion. Binding was prevented by prior incubation of hippocampal homogenates with a protein tyrosine phosphatase or by a competing peptide for the Src SH2 domain. Ischemia induced a marked increase in the tyrosine phosphorylation of several proteins in the postsynaptic density (PSD), including NR2A and NR2B, but had no effect on the amounts of individual NMDA receptor subunits in the PSD. The level of Src and Fyn in PSDs, but not in other subcellular fractions, was increased after ischemia. The ischemia-induced increase in the interaction of NR2A and NR2B with the SH2 domains of Src and Fyn suggests a possible mechanism for the recruitment of signaling proteins to the PSD and may contribute to altered signal transduction in the postischemic hippocampus.

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