Difference between revisions of "Pseudophosphatases (obsolete)"

Revision as of 05:13, 2 October 2015

Human pseudophosphatases

PTPs

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 receptor PTP stability, specificity, and dimerization [1, 2]. Because the first phosphatase domains are active, these receptor PTPs are active at protein level. These phosphatases include:

• Subfamily PTPRA: PTPRA and PTPRE
• Subfamily PTPRC: PTPRC
• Subfamily PTPRD: PTPRD, PTPRF and PTPRS
• Subfamily PTPRG: PTPRG and PTPRZ1
• Subfamily PTPRK: PTPRK, PTPRM, PTPRT and PTPRU

PTPN23 subfamily

The PTPN23 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].

DSPs

STYX subfamily

The STYX subfamily has a single member in human, STYX. It binds to phosphorylated tyrosine to module signaling [6]. STYX localizes to the nucleus, competes with DUSP4 for binding to ERK, and acts as a nuclear anchor that regulates ERK nuclear export [7].

STYXL1 subfamily

The STYXL1 subfamily has a single member in human, STYXL1 (MK-STYX). STYXL1 binds to phosphatase PTPMT1 and modulates its activity [8, 9]. However, it is unclear whether the interaction between STYXL1 and PTPMT1 is mediated by the inactive phosphatase domain of STYXL1.

One of the five of DSP3 subfamily: DUSP27

The function of DUSP27 is unknown, so is its catalytically inactive phosphatase domain.

PTEN-like phosphatases

Auxilin subfamily

There are two members of [[Phosphatase_Subfamily_Auxilin|auxilin subfamily] in human, GAK and DNAJC6. Both GAK and DNAJC6 phosphatase domains have been shown to bind to phospholipids [10, 11]. The phosphatase domains of both are predicted to be inactive due to arginine in catalytic motif Cx5R is replaced by alanine.

Tension subfamily

References

1. Error fetching PMID 12376545: [denHertog02]
2. Error fetching PMID 19167335: [Barr09]
3. Error fetching PMID 19340315: [Gingras09]
4. Error fetching PMID 21724833: [Lin11]
5. Error fetching PMID 18762272: [Mariotti09]
6. Error fetching PMID 9757831: [Wishart98]
7. Error fetching PMID 23847209: [Reiterer13]
10. Error fetching PMID 16895969: [Lee]
11. Error fetching PMID 23823232: [Kalli]
12. Error fetching PMID 20097759: [Caromile10]
13. Error fetching PMID 24064037: [Kharitidi13]