Phosphatase Family HP1

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Phosphatase Classification: Fold HP: Superfamily HP (histidine phosphatase): HP, branch1 family

Subfamilies

PGAM
PGAM5
TIGAR
STS
PFKFB
Cele-STS-like
TFC7
HP1LE
Dicty-HP1-sf1
STSs/TULAs

There are two TULAs in human, UBASH3A (STS-2 or TULA-1) and UBASH3B (STS-1 or TULA-2). Both TULAs negatively regulate the endocytosis of receptor tyrosine kinases. The UBA domain of TULA-1 and SH3-dependent Cbl-binding are required for this function. TULA-1 (STS-2) is a lymphoid protein, whereas TULA-2 (STS-1) is expressed ubiquitously. It has been shown that TULA-2 can dephosphorylate phospho-tyrosines on EGFR and Syk. The histidine phosphatase domain of TULA-2, but not of TULA-1, dephosphorylates the EGFR at multiple tyrosines, and thereby terminating its signalling and endocytosis [1]. TULA-2 decreases tyrosine phosphorylation of Syk in vivo and in vitro. Inactivated TULA-2 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 TULA-2. However, the same assay on TULA-1 shows the phosphatase activity of TULA-1 is negligible compared to TULA-2 [2]. TULA-1 is present in lobe-finned fish, birds and mammals, but not other bony fishes. TULA-2 emerged earlier than TULA-1, which is found in most metazoan, from sponge to nematodes, insects, fishes, birds, and mammals.


References

  1. Raguz J, Wagner S, Dikic I, and Hoeller D. Suppressor of T-cell receptor signalling 1 and 2 differentially regulate endocytosis and signalling of receptor tyrosine kinases. FEBS Lett. 2007 Oct 2;581(24):4767-72. DOI:10.1016/j.febslet.2007.08.077 | PubMed ID:17880946 | HubMed [STS_1]
  2. Agrawal R, Carpino N, and Tsygankov A. TULA proteins regulate activity of the protein tyrosine kinase Syk. J Cell Biochem. 2008 Jun 1;104(3):953-64. DOI:10.1002/jcb.21678 | PubMed ID:18189269 | HubMed [STS_2]
  3. Takeda K, Komuro Y, Hayakawa T, Oguchi H, Ishida Y, Murakami S, Noguchi T, Kinoshita H, Sekine Y, Iemura S, Natsume T, and Ichijo H. Mitochondrial phosphoglycerate mutase 5 uses alternate catalytic activity as a protein serine/threonine phosphatase to activate ASK1. Proc Natl Acad Sci U S A. 2009 Jul 28;106(30):12301-5. DOI:10.1073/pnas.0901823106 | PubMed ID:19590015 | HubMed [PGAM5_1]
  4. Wang Z, Jiang H, Chen S, Du F, and Wang X. The mitochondrial phosphatase PGAM5 functions at the convergence point of multiple necrotic death pathways. Cell. 2012 Jan 20;148(1-2):228-43. DOI:10.1016/j.cell.2011.11.030 | PubMed ID:22265414 | HubMed [PGAM5_2]
  5. Chen G, Han Z, Feng D, Chen Y, Chen L, Wu H, Huang L, Zhou C, Cai X, Fu C, Duan L, Wang X, Liu L, Liu X, Shen Y, Zhu Y, and Chen Q. A regulatory signaling loop comprising the PGAM5 phosphatase and CK2 controls receptor-mediated mitophagy. Mol Cell. 2014 May 8;54(3):362-77. DOI:10.1016/j.molcel.2014.02.034 | PubMed ID:24746696 | HubMed [chen14]
All Medline abstracts: PubMed | HubMed