Table I.

Summary of protein phosphatase gene types in Arabidopsis and human

Protein phosphatase genes are summarized from this study, plus the following references: Kerk et al. (2002); Kim et al. (2002); Schweighofer et al. (2004); Kerk (2007); and Moorhead et al. (2007). Multiple protein isoforms are often transcribed from the same gene, but are ignored in this table, for simplicity. A number of additional sequences have been identified that contain similarity to the Arabidopsis genes, but have been rejected because they lack critical class-specific catalytic residues (see Kerk, 2007). Since the report in Kerk et al. (2002), excluding the data from this study, the following changes have occurred to the Arabidopsis protein phosphatase gene set: three PPPs have been added (At1g18480 [Bacterial-like]; At3g19980 [PP6]; At5g43380 [PP1]); six DSPs have been added (At3g09100, At3g19420 [PTEN homolog], At3g62010, At4g03960, At5g01290, and At5g28210); eight PP2Cs have been added (At2g30170, At2g46920, At4g03415, At4g11040, At4g16580, At1g17550, At4g33500, and At5g66720); one DSP has been deleted (At3g55270—reannotated with a greatly shortened DSP domain); and one PP2C has been deleted (At1g75010—determined to be a false positive). N/A, Not applicable.

Protein Phosphatase FamilySubclassArabidopsis GenesHuman Genes
Ser/Thr phosphatase
    PPP familyTotal2613
PP193
PP2A52
PP2B03
PP421
PP511
PP621
PP712
Othera6N/A
    PPM family (PP2C)7618
PTP superfamily (CX5R)
    Class I PTP (classic)Total138
Receptor021
Nonreceptor117
    SSU7211
    Class I PTP (DSPs)Total2261
MAPKP011
Slingshots03
PRLsb03
Atypical DSPb319
CDC1404
PTENb35
Myotubularinsb216
Otherc15N/A
    Class II PTPs (CDC25)None3
    Class III PTPs (LMWPTP)11
Asp-based catalysis (DXDXT/V)
    FCP-like198
    HAD family (chronophins)31
    HAD family (EYA)14
150 Total148 Total
  • a Phosphatases of known family but with no direct homologs to characterized mammalian proteins (includes At1g03445, At1g07010, At1g08420, At1g18480, At2g27210, and At4g03080).

  • b Lipid phosphatases and phosphatases of unknown substrate belonging to the various families.

  • c Includes At1g05000, At2g04550, At2g32960, At2g35680, At3g02800, At3g06110, At3g09100, At3g23610, At3g62010, At4g03960, At5g01290, At5g16480, At5g23720, At5g28210, and At5g56610.