Table 2.
Various isoforms of different subunits of PP2A and their nomenclature, chromosomal location and normal/aberrant expression in various cancer and normal tissues.
| Subunit | Gene | Isoform | Other name | Chromosome number | Normal tissue distribution | Subcellular distribution | Aberrant tissue distribution |
|---|---|---|---|---|---|---|---|
| Scaffold (A) | PPP2R1A | α | PR65α,PP2A-Aα | 19q13.33 | Ubiquitously expressed in all the tissues [22]. | Cytosol | Lung, breast, melanoma, endometrial and ovarian cancer [75]. |
| PPP2R1B | β | PR65β,PP2A-Aβ | 11q23.2 | Ubiquitously expressed and highly expressed in ovary (oogenesis) [22]. | Cytosol | Lung, Breast, colon, ovarian, B-CLL [75]. | |
| Catalytic (C) | PPP2CA | α | PP2Acα | 5q31.1 | Brain and Heart (HE) [19, 100]. | Cytoplasm and Nucleus | Prostate [101]. |
| PPP2CB | β | PP2Acβ | 8p12 | Brain and Heart (HE) [19, 100]. | Cytoplasm and Nucleus | - | |
| Regulatory (B) | PPP2R2A | α | PR55α,PP2ABα | 8p21.1 | Widely distributed in all tissues [16, 24, 30]. | Membranes, cytoplasm, Microtubules Nucleus. Golgi complex, endoplasmic reticulum and neurofilaments | AML, prostate P [85, 88]. |
| PPP2R2B | β | PR55β,PP2ABβ | 5q31-5q32 | Brain and testis(HE)[16]. | Cytosol | - | |
| PPP2R2C | γ | PR55γ, PP2ABγ | 4p16.1 | Brain (SE) [27]. | Mainly in Cytoskeletal fraction | Lung cancer, melanoma [102]. | |
| PPP2R2D | δ | PR55δ, PP2ABδ | 10q26.3 | Wide spread distribution in tissues, Testis (HE) [28]. | Cytosol | - | |
| Regulatory(B’) | PPP2R5A | α | PR56/61α,PP2AB’α | 1q32.2-q32.3 | Cardiac tissues and skeletal muscles (HE)[103]. | Cytoplasm | - |
| PPP2R5B | β | PR56/61β,PP2AB’β | 11q12-q13 | Brain (HE) [103, 104]. | Cytoplasm | - | |
| PPP2R5C | γl, 2,3 | PR56/61γ, PP2AB’γ | 14q32 | Cardiac tissues and skeletal muscles (HE) [103-105]. | Cytoplasm and Nucleus | Lung cancer (HE) reduced level in melanoma cells [86, 87]. | |
| PPP2R5D | δ | PR56/61δ, PP2AB’δ | 6p21.1 | Primarily exist in brain [103, 106]. | Cytoplasm, Nucleus, Mitochondria, Microsomes | - | |
| PPP2R5E | ε | PR56/61ε, PP2AB’ε | 14q23.1 | Primarily exist in brain [103] | Cytoplasm | Breast cancer, Soft tissue sarcoma [107]. | |
| Regulatory(B”) | PPP2R3A | α | PR130,B”α1 | 3q22.1 | Brain(HE), heart, Lung, kidney and muscle [16]. | Centrosome and Golgi complex | - |
| PPP2R3A | α | PR72, B”α2 | 3q22.1 | Heart(HE) and skeletal muscle [16]. | Cytosol and nucleus | - | |
| PPP2R3B | β | PR70, PR48, B”β | Xp22.33, Y11.3 | Placenta [108]. | Nucleus | - | |
| PPP2R3C | γ | G5PR, G4-1 | 14q13.2 | During developmental process expressed in fetal brain [109]. | Nucleus | - | |
| PPP2R3D | δ | PR59, B”δ | Cardiac tissue, Kidney and Lungs [33]. | Nucleus | - | ||
| Regulatory(B’”) | STRN | Striatin, PR110 | 2p22.2 | Brain [110]. | Membrane and cytoplasm | - | |
| STRN3 | SG2NA | 14q13-q21 | Neurons [110]. | Nucleus | - | ||
| PPP2R4 | PTPA, PR53 | 9q34 | Widely expressed [20, 111, 112]. | Cytosol, Nucleus | - |
HE-Highly expressed, SE –Specific expression