SLP-76 Is a Substrate of the High Affinity IgE Receptor-stimulated Protein Tyrosine Kinases in Rat Basophilic Leukemia Cells

Hendricks-Taylor, L. Ranee; Motto, David G.; Zhang, Juan; Siraganian, Reuben P.; Koretzky, Gary A.

doi:10.1074/jbc.272.2.1363

Cited by 65 publications

(42 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In vitro, a 14-amino acid long peptide corresponding to the COOH-terminal region of Syk bound SLP-65 when phosphorylated at the tyrosine corresponding to Tyr-624 of rat Syk, whereas in vivo BCR-mediated signaling was impaired when this tyrosine was mutated to phenylalanine together with decreased recruitment of SLP-65 to the plasma membrane (33). In mast cells, SLP-76, a homolog to SLP-65, is tyrosine phosphorylated after receptor aggregation and is essential for Fc⑀RI-mediated signaling (63)(64)(65). A synthetic peptide corresponding to the tail sequence with both Tyr-624 and Tyr-625 phosphorylated precipitated SLP-76, however, we did not detect co-precipitation of Syk and SLP-76 from lysates of RBL-2H3 cells (data not shown).…”

Section: Discussionmentioning

confidence: 99%

Tyrosines in the Carboxyl Terminus Regulate Syk Kinase Activity and Function

Castro

Zhang

Jamur

et al. 2010

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

The Syk tyrosine kinase family plays an essential role in immunoreceptor tyrosine-based activation motif (ITAM) signaling. The binding of Syk to tyrosine-phosphorylated ITAM subunits of immunoreceptors, such as Fc⑀RI on mast cells, results in a conformational change, with an increase of enzymatic activity of Syk. This conformational change exposes the COOH-terminal tail of Syk, which has three conserved Tyr residues (Tyr-623, Tyr-624, and Tyr-625 of rat Syk). To understand the role of these residues in signaling, wild-type and mutant Syk with these three Tyr mutated to Phe was expressed in Syk-deficient mast cells. There was decreased Fc⑀RI-induced degranulation, nuclear factor for T cell activation and NFB activation with the mutated Syk together with reduced phosphorylation of MAP kinases p38 and p42/44 ERK. In non-stimulated cells, the mutated Syk was more tyrosine phosphorylated predominantly as a result of autophosphorylation. In vitro, there was reduced binding of mutated Syk to phosphorylated ITAM due to this increased phosphorylation. This mutated Syk from non-stimulated cells had significantly reduced kinase activity toward an exogenous substrate, whereas its autophosphorylation capacity was not affected. However, the kinase activity and the autophosphorylation capacity of this mutated Syk were dramatically decreased when the protein was dephosphorylated before the in vitro kinase reaction. Furthermore, mutation of these tyrosines in the COOH-terminal region of Syk transforms it to an enzyme, similar to its homolog ZAP-70, which depends on other tyrosine kinases for optimal activation. In testing Syk mutated singly at each one of the tyrosines, Tyr-624 but especially Tyr-625 had the major role in these reactions. Therefore, these results indicate that these tyrosines in the tail region play a critical role in regulating the kinase activity and function of Syk.Syk and ZAP-70 are members of a tyrosine kinase family one or both of which are expressed in most hematopoietic cells (1-5). Structurally Syk/ZAP-70 consists of two Src-homology 2 domains (SH2) 3 and a kinase domain followed by a short COOH-terminal extension (tail). The inter-SH2 domain is located between the NH 2 -terminal SH2 (SH2-N) and COOHterminal SH2 (SH2-C), whereas the linker region is between the SH2-C and the kinase domains (6, 7). An alternatively spliced form of Syk, termed SykB, lacks a 23-amino acid sequence in the linker domain (8). Although both isoforms are expressed in immune cells such as the RBL-2H3 rat mast cell line, Syk is more efficient than SykB in immunoreceptor signaling (8,9). Syk is expressed in B cells, mast cells, immature T cells, and platelets, whereas ZAP-70 is in T cells and natural killer cells (3, 10). Syk and ZAP-70 are essential for signal transduction from cell surface immunoreceptors (10 -12). These receptors on many hematopoietic cells such as T, B, and mast cells have subunits, which contain a sequence named the immunoreceptor tyrosine-based activation motif (ITAM) which contains two tyrosine residues (13...

show abstract

Section: Discussionmentioning

confidence: 99%

Tyrosines in the Carboxyl Terminus Regulate Syk Kinase Activity and Function

Castro

Zhang

Jamur

et al. 2010

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…Syk PTK is then recruited to the phosphorylated ITAMs of ␥-chain via its Src homology region 2 (SH2) domains, becomes tyrosine phosphorylated, and is activated by Lyn (5-7). The activated PTKs phosphorylate a number of signaling molecules, including phospholipase C␥ (PLC␥) (8,9), Vav (10), SH2 domain-containing leukocyte protein of 76 kDa (SLP-76) (11), linker for activation of T cells (LAT) (12), and linker for activation of B cells/non-T cell activation linker (13). Phosphorylation of these proteins induces calcium (Ca 2ϩ ) mobilization and activation of MAPKs and is ultimately converged into degranulation and production of cytokines.…”

Section: Positive and Negative Regulation Of High Affinity Ige Receptormentioning

confidence: 99%

Positive and Negative Regulation of High Affinity IgE Receptor Signaling by Src Homology Region 2 Domain-Containing Phosphatase 1

Nakata

Yoshimaru

Suzuki

et al. 2008

The Journal of Immunology

View full text Add to dashboard Cite

Src homology region 2 domain-containing phosphatase 1 (SHP-1), a cytoplasmic protein tyrosine phosphatase, plays an important role for the regulation of signaling from various hematopoietic cell receptors. Although SHP-1 is shown to be a negative signal modulator in mast cells, its precise molecular mechanisms are not well defined. To elucidate how SHP-1 regulates mast cell signaling, we established bone marrow-derived mast cells from SHP-1-deficient motheaten and wild-type mice and analyzed downstream signals induced by cross-linking of high affinity IgE receptor, FcεRI. Upon FcεRI ligation, motheaten-derived bone marrow-derived mast cells showed enhanced tyrosine phosphorylation of Src homology region 2 domain-containing leukocyte protein of 76 kDa (SLP-76) and linker for activation of T cells, activation of mitogen-activated protein kinases and gene transcription and production of cytokine. Because the activity of Syk, responsible for the phosphorylation of SLP-76 and linker for activation of T cells, is comparable irrespective of SHP-1, both molecules might be substrates of SHP-1 in mast cells. Interestingly, the absence of SHP-1 expression disrupted the association between SLP-76 and phospholipase Cγ, which resulted in the decreased phospholipase Cγ phosphorylation, calcium mobilization, and degranulation. Collectively, these results suggest that SHP-1 regulates FcεRI-induced downstream signaling events both negatively and positively by functioning as a protein tyrosine phosphatase and as an adaptor protein contributing to the formation of signaling complex, respectively.

show abstract

“…SLP-76 is a leukocyte-specific cytoplasmic protein comprised of acidic region at the NH 2 terminus containing three tyrosine residues that can be phosphorylated by Syk family PTKs, followed by a proline-rich region and a COOH-terminal SH2 domain (28). This molecule is involved in the regulation of signaling events initiated by TCR (28 -33) and Fc⑀RI (34). Recently, it was demonstrated that SLP-76 is a direct substrate of SHP-1 in T cells and NK cells, and that dephosphorylation of SLP-76 by SHP-1 is a crucial mechanism for the negative regulation of lymphocyte activation by inhibitory receptors (35).…”

mentioning

confidence: 99%

Src Homology Region 2 (SH2) Domain-Containing Phosphatase-1 Dephosphorylates B Cell Linker Protein/SH2 Domain Leukocyte Protein of 65 kDa and Selectively Regulates c-Jun NH2-Terminal Kinase Activation in B Cells

Mizuno

Tagawa

Mitomo

et al. 2000

The Journal of Immunology

View full text Add to dashboard Cite

Src homology region 2 (SH2) domain-containing phosphatase-1 (SHP-1) is a cytosolic protein tyrosine phosphatase containing two SH2 domains in its NH2 terminus. That immunological abnormalities of the motheaten and viable motheaten mice are caused by mutations in the gene encoding SHP-1 indicates that SHP-1 plays important roles in lymphocyte differentiation, proliferation, and activation. To elucidate molecular mechanisms by which SHP-1 regulates BCR-mediated signal transduction, we determined SHP-1 substrates in B cells using the substrate-trapping approach. When the phosphatase activity-deficient form of SHP-1, in which the catalytic center cysteine (C453) was replaced with serine (SHP-1-C/S), was introduced in WEHI-231 cells, tyrosine phosphorylation of a protein of about 70 kDa was strongly enhanced. Immunoprecipitation and Western blot analyses revealed that this protein is the B cell linker protein (BLNK), also named SH2 domain leukocyte protein of 65 kDa, and that upon tyrosine phosphorylation BLNK binds to SHP-1-C/S in vitro. In vitro kinase assays demonstrated that hyperphosphorylation of BLNK in SHP-1-C/S-expressing cells was not due to enhanced activity of Lyn or Syk. Furthermore, BCR-induced activation of c-Jun NH2-terminal kinase was shown to be significantly enhanced in SHP-1-C/S transfectants. Taken collectively, our results suggest that BLNK is a physiological substrate of SHP-1 in B cells and that SHP-1 selectively regulates c-Jun NH2-terminal kinase activation.

show abstract

SLP-76 Is a Substrate of the High Affinity IgE Receptor-stimulated Protein Tyrosine Kinases in Rat Basophilic Leukemia Cells

Cited by 65 publications

References 53 publications

Tyrosines in the Carboxyl Terminus Regulate Syk Kinase Activity and Function

Tyrosines in the Carboxyl Terminus Regulate Syk Kinase Activity and Function

Positive and Negative Regulation of High Affinity IgE Receptor Signaling by Src Homology Region 2 Domain-Containing Phosphatase 1

Src Homology Region 2 (SH2) Domain-Containing Phosphatase-1 Dephosphorylates B Cell Linker Protein/SH2 Domain Leukocyte Protein of 65 kDa and Selectively Regulates c-Jun NH2-Terminal Kinase Activation in B Cells

Contact Info

Product

Resources

About