Difference between revisions of "Pseudophosphatases (obsolete)"

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(Human pseudophosphatases)
(PTPN23 subfamily)
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* [[Phosphatase_Subfamily_PTPRG|Subfamily PTPRK]]: PTPRK, PTPRM, PTPRT and PTPRU
 
* [[Phosphatase_Subfamily_PTPRG|Subfamily PTPRK]]: PTPRK, PTPRM, PTPRT and PTPRU
  
===== [[Phosphatase_Subfamily_PTPN23|PTPN23 subfamily]] =====
+
=== [[Phosphatase_Subfamily_PTPN23|PTPN23 subfamily]] ===
 
The subfamily has a single member in human, PTPN23 (HD-PTP). Its catalytic activity is plausible. It has been reported to be catalytically inactive, - no phosphatase activity toward tyrosine or lipid. It was proposed that serine at position 1452 within Cx5R catalytic motif caused the inactivity. Replacing serine with alanine, which is found in catalytically active PTPs, can restore the phosphatase activity <cite>Gingras09</cite>. However, another study found SRC, E-cadherin, and beta-catenin are direct substrates of PTPN23 <cite>Lin11</cite>. But, yet another study showed that PTPN23 did not modulate the levels of Src phosphorylation both in vitro and in vivo <cite>Mariotti09</cite>.
 
The subfamily has a single member in human, PTPN23 (HD-PTP). Its catalytic activity is plausible. It has been reported to be catalytically inactive, - no phosphatase activity toward tyrosine or lipid. It was proposed that serine at position 1452 within Cx5R catalytic motif caused the inactivity. Replacing serine with alanine, which is found in catalytically active PTPs, can restore the phosphatase activity <cite>Gingras09</cite>. However, another study found SRC, E-cadherin, and beta-catenin are direct substrates of PTPN23 <cite>Lin11</cite>. But, yet another study showed that PTPN23 did not modulate the levels of Src phosphorylation both in vitro and in vivo <cite>Mariotti09</cite>.
  

Revision as of 00:34, 2 October 2015

Human pseudophosphatases

Second phosphatase domain (D2) in receptor PTPs

Most receptor PTPs have two tandem phosphatase domains. The 2nd phosphatase domain has no or negligible activity. The 2nd domain can interact with 1st domain in both intra- and intermolecular manners, therefore regulating RPTP stability, specificity, and dimerization [1, 2].

These phosphatases include:

PTPN23 subfamily

The subfamily has a single member in human, PTPN23 (HD-PTP). Its catalytic activity is plausible. It has been reported to be catalytically inactive, - no phosphatase activity toward tyrosine or lipid. It was proposed that serine at position 1452 within Cx5R catalytic motif caused the inactivity. Replacing serine with alanine, which is found in catalytically active PTPs, can restore the phosphatase activity [3]. However, another study found SRC, E-cadherin, and beta-catenin are direct substrates of PTPN23 [4]. But, yet another study showed that PTPN23 did not modulate the levels of Src phosphorylation both in vitro and in vivo [5].

Auxilin subfamily

There are two members of auxilin subfamily in human, GAK and DNAJC6. Both GAK and DNAJC6 phosphatase domains have been shown to bind phospholipids [6, 7]. The phosphatase domains of both are predicted to be inactive due to arginine in catalytic motif Cx5R is replaced by alanine.

References

  1. Blanchetot C, Tertoolen LG, Overvoorde J, and den Hertog J. Intra- and intermolecular interactions between intracellular domains of receptor protein-tyrosine phosphatases. J Biol Chem. 2002 Dec 6;277(49):47263-9. DOI:10.1074/jbc.M205810200 | PubMed ID:12376545 | HubMed [denHertog02]
  2. Barr AJ, Ugochukwu E, Lee WH, King ON, Filippakopoulos P, Alfano I, Savitsky P, Burgess-Brown NA, Müller S, and Knapp S. Large-scale structural analysis of the classical human protein tyrosine phosphatome. Cell. 2009 Jan 23;136(2):352-63. DOI:10.1016/j.cell.2008.11.038 | PubMed ID:19167335 | HubMed [Barr09]
  3. Gingras MC, Zhang YL, Kharitidi D, Barr AJ, Knapp S, Tremblay ML, and Pause A. HD-PTP is a catalytically inactive tyrosine phosphatase due to a conserved divergence in its phosphatase domain. PLoS One. 2009;4(4):e5105. DOI:10.1371/journal.pone.0005105 | PubMed ID:19340315 | HubMed [Gingras09]
  4. Lin G, Aranda V, Muthuswamy SK, and Tonks NK. Identification of PTPN23 as a novel regulator of cell invasion in mammary epithelial cells from a loss-of-function screen of the 'PTP-ome'. Genes Dev. 2011 Jul 1;25(13):1412-25. DOI:10.1101/gad.2018911 | PubMed ID:21724833 | HubMed [Lin11]
  5. Mariotti M, Castiglioni S, Garcia-Manteiga JM, Beguinot L, and Maier JA. HD-PTP inhibits endothelial migration through its interaction with Src. Int J Biochem Cell Biol. 2009 Mar;41(3):687-93. DOI:10.1016/j.biocel.2008.08.005 | PubMed ID:18762272 | HubMed [Mariotti09]
  6. Lee DW, Wu X, Eisenberg E, and Greene LE. Recruitment dynamics of GAK and auxilin to clathrin-coated pits during endocytosis. J Cell Sci. 2006 Sep 1;119(Pt 17):3502-12. DOI:10.1242/jcs.03092 | PubMed ID:16895969 | HubMed [Lee]
  7. Kalli AC, Morgan G, and Sansom MS. Interactions of the auxilin-1 PTEN-like domain with model membranes result in nanoclustering of phosphatidyl inositol phosphates. Biophys J. 2013 Jul 2;105(1):137-45. DOI:10.1016/j.bpj.2013.05.012 | PubMed ID:23823232 | HubMed [Kalli]
  8. Caromile LA, Oganesian A, Coats SA, Seifert RA, and Bowen-Pope DF. The neurosecretory vesicle protein phogrin functions as a phosphatidylinositol phosphatase to regulate insulin secretion. J Biol Chem. 2010 Apr 2;285(14):10487-96. DOI:10.1074/jbc.M109.066563 | PubMed ID:20097759 | HubMed [Caromile10]
  9. Kharitidi D, Manteghi S, and Pause A. Pseudophosphatases: methods of analysis and physiological functions. Methods. 2014 Jan 15;65(2):207-18. DOI:10.1016/j.ymeth.2013.09.009 | PubMed ID:24064037 | HubMed [Kharitidi13]
All Medline abstracts: PubMed | HubMed