Phosphatases are classified by protein structural fold of the catalytic domain, and sub-classified by families and subfamilies based on the sequence of the phosphatase domains as well as by sequences outside of the catalytic domain, and known biochemical and biological functions .
Classification Chart of Protein Phosphatases
|Fold||Superfamily||Family||Substrate||Present in human|
|DSP||pTyr, pSer/pThr, small molecule||Yes|
|AP||AP||AP||pTyr, perhaps pSer/pThr||Yes|
|HP2||pTyr, small molecules||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; PPPL: PPP-like; 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
Both FCPs of HAD fold and SSU72 of CC2 fold can dephosphorylate CTD.
Notes on the PTPLA/PTP-like family that was claimed to be a phosphatase, but probably is not.
Some phosphatases only dephosphorylate non-protein substrates, as far as known.
- What are the single-gene subfamilies in nine genomes. We keep them because they are found in at least two genera, although they are not found in the other genome among the nine genomes: dicty, budding yeast, monosiga, sponge, nematostella, C. elegans, Drosophila, sea urchin, and human.