Phosphatase classification
Phosphatases were first clustered by sequence similarity in the phosphatase domain, and additional information from domains outside of the catalytic domain, from evolutionary conservation, and from known functions was added. The result is a hybrid classification, in which no criterion is universally satisfied, but aims to be of practical use to a range of phosphatase interests. The classification grows as new phosphatomes are sequenced.
Classification Chart of Protein Phosphatases
| Fold | Superfamily | Family | Substrate | Present in human |
|---|---|---|---|---|
| CC1 | CC1 | PTP | pTyr | Yes |
| DSP | pTyr, pSer/pThr, small molecule | Yes | ||
| PTEN | lipid | Yes | ||
| Myotubularin | lipid | Yes | ||
| SAC | lipid | Yes | ||
| Paladin | inactive | Yes | ||
| OCA | ? | |||
| CC2 | CC2 | LMWPTP | pTyr | Yes |
| SSU72 | pSer | Yes | ||
| ArsC | Arsenate | |||
| CC3 | CC3 | CDC25 | pTyr, pThr | Yes |
| HAD | HAD | EYA | pTyr | Yes |
| FCP | pSer | Yes | ||
| NagD | pTyr, pSer | Yes | ||
| PPPL | PPPL | PPP | pSer/pThr | Yes |
| PAP | ? | Yes | ||
| PPM | PPM | PPM | pSer/pThr | Yes |
| AP | AP | AP | pTyr, perhaps pSer/pThr | Yes |
| HP | HP | HP1 | pTyr, pSer/pThr | Yes |
| HP2 | pTyr, small molecules | Yes | ||
| PHP | PHP | PHP | pHis | Yes |
| RTR1 | RTR1 | RTR1 | pSer of CTD repeats | Yes |
Synonymns: CC3, Rhodanese; PPM, PP2C.
Abbreviations: CC1, Cysteine-based Class I; CC2, Cysteine-based Class II; CC3, Cysteine-based Class III; MTDP, MeTallo-Dependent Phosphatase; PAP, Purple Acid Phosphatase; AP, Alkaline Phosphatase; HP, Histidine Phosphatase; HP1, Histidine Phosphatase, branch 1; HP2, Histidine Phosphatase, branch 2; CTD, RNA Poly II C-Terminal Domain.
Notes of classification
PTPLA is a dubious phosphatase
Notes on the PTPLA/PTP-like family that was claimed to be a phosphatase, but probably is not.
Non-protein phosphatases
Some phosphatases only dephosphorylate non-protein substrates, as far as known.
