Difference between revisions of "Phosphatase Subfamily STS"
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| + | Human STS subfamily acts as downregulators of receptor-induced activation in several cell types, including T cells and platelets. Deletion of both family members in mice has been shown to result in hyperresponsiveness of T cells to T-cell receptor (TCR)/CD3 complex engagement. | ||
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STS-1 can dephosphorylate phospho-tyrosines on EGFR and Syk. The histidine phosphatase domain of STS-1, but not of STS-2, dephosphorylates the EGFR at multiple tyrosines, and thereby terminating its signalling and endocytosis <cite>STS_1</cite>. | STS-1 can dephosphorylate phospho-tyrosines on EGFR and Syk. The histidine phosphatase domain of STS-1, but not of STS-2, dephosphorylates the EGFR at multiple tyrosines, and thereby terminating its signalling and endocytosis <cite>STS_1</cite>. | ||
STS-1 decreases tyrosine phosphorylation of Syk in vivo and in vitro. Inactivated STS-1 increases tyrosine phosphorylation of Syk in cells co-transfected to overexpress these proteins, thus acting as a dominant-negative form that suppresses dephosphorylation of Syk caused by endogenous STS-1. However, the same assay on STS-2 shows the phosphatase activity of STS-2 is negligible compared to STS-1 <cite>STS_2</cite>. | STS-1 decreases tyrosine phosphorylation of Syk in vivo and in vitro. Inactivated STS-1 increases tyrosine phosphorylation of Syk in cells co-transfected to overexpress these proteins, thus acting as a dominant-negative form that suppresses dephosphorylation of Syk caused by endogenous STS-1. However, the same assay on STS-2 shows the phosphatase activity of STS-2 is negligible compared to STS-1 <cite>STS_2</cite>. | ||
| − | Both human STSs negatively regulate the endocytosis of receptor tyrosine kinases. The UBA domain of STS-2 and SH3-dependent Cbl-binding are required for this function. STS-2 is | + | Both human STSs negatively regulate the endocytosis of receptor tyrosine kinases. The UBA domain of STS-2 and SH3-dependent Cbl-binding are required for this function. STS-2 is predominantly in naive and mature T cells , whereas STS-1 is expressed ubiquitously. |
===References=== | ===References=== | ||
Revision as of 04:19, 3 January 2015
Phosphatase Classification: Fold HP: Superfamily HP (histidine phosphatase): HP, branch1 family: Subfamily STS
Contents
Evolution
STS subfamily is found in most metazoan. Human has two STSs: STS-1 (TULA-2 or UBASH3B) and STS-2 (TULA-1 or UBASH3A). STS-2 is present in lobe-finned fish, birds and mammals, but not other bony fishes. STS-1 emerged earlier than STS-2, which is found in most metazoan, from sponge to nematodes, insects, fishes, birds, and mammals.
Domain
STS has three domains: UBA, SH3 and HP2 phosphatase domain.
Functions
Human STS subfamily acts as downregulators of receptor-induced activation in several cell types, including T cells and platelets. Deletion of both family members in mice has been shown to result in hyperresponsiveness of T cells to T-cell receptor (TCR)/CD3 complex engagement.
STS-1 can dephosphorylate phospho-tyrosines on EGFR and Syk. The histidine phosphatase domain of STS-1, but not of STS-2, dephosphorylates the EGFR at multiple tyrosines, and thereby terminating its signalling and endocytosis [1].
STS-1 decreases tyrosine phosphorylation of Syk in vivo and in vitro. Inactivated STS-1 increases tyrosine phosphorylation of Syk in cells co-transfected to overexpress these proteins, thus acting as a dominant-negative form that suppresses dephosphorylation of Syk caused by endogenous STS-1. However, the same assay on STS-2 shows the phosphatase activity of STS-2 is negligible compared to STS-1 [2].
Both human STSs negatively regulate the endocytosis of receptor tyrosine kinases. The UBA domain of STS-2 and SH3-dependent Cbl-binding are required for this function. STS-2 is predominantly in naive and mature T cells , whereas STS-1 is expressed ubiquitously.
References
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