Role of PRMTs in cancer: Could minor isoforms be leaving a mark?

Table 1 Protein arginine methyltransferases in cancer cells

PRMT	Cancer type	Role(s) in cancer	Ref.
PRMT1	Breast cancer, Lung cancer, Colon cancer, Bladder cancer, Acute myeloid leukemia, Mixed lineage leukemia	Cell proliferation and survival, Transformation, Resistance to DNA damaging agents, Invasion	[13,15-17,19, 21,36-38]
PRMT2	Breast cancer	Cell proliferation and invasion	[22,72]
PRMT3	Breast cancer	Cell survival	[101,102]
CARM1/PRMT4	Breast cancer, Prostate cancer, Colorectal cancer	Cell proliferation	[12,14,77-79,88]
PRMT5	Lung cancer, Leukemia, Lymphoma, Melanoma, Gastric cancer, Colorectal cancer	Cell proliferation, Transformation, Invasion, Resistance to DNA damaging agents	[18,103-109]
PRMT6	Lung cancer, Bladder cancer	Cell proliferation	[17,110]
PRMT7	Breast cancer	Resistance to DNA damaging agents	[27,91,92,94]
PRMT8	ND	ND
PRMT9	ND	ND

ND: Not determined; PRMT: Protein arginine methyltransferase.

Table 2 Protein arginine methyltransferase isoform specific subcellular localization and current cancer cell types in which they have been shown to be expressed

PRMT isoform	Molecular weight (kDa)	Subcellular localization	Cancer cell type	Ref.
PRMT1v1	40.5	Predominantly nuclear	Breast cancer cell lines and tumour samples, cervical cancers cells	[21]
PRMT1v2	42.5	Predominantly cytoplasmic	Breast cancer cell lines and tumour samples, cervical cancers cells	[21,39]
PRMT1v3	39.9	Cytoplasmic and nuclear	Breast cancer cell lines and tumour samples	[21]
PRMT1v4	40.1	Cytoplasmic and nuclear	Breast cancer cell lines	[21]
PRMT1v5	39.4	Cytoplasmic and nuclear	Breast cancer cell lines	[21]
PRMT1v6	37.7	Cytoplasmic and nuclear	Breast cancer cell lines	[21]
PRMT1v7	36.7	Predominantly nuclear	Breast cancer cell lines	[21]
PRMT2	48.5	Predominantly nuclear, excluding nucleoli	Breast cancer cell lines and tumour samples	[22,72]
PRMT2L2	32	Predominantly cytoplasmic	Breast cancer cell lines and tumour samples	[72]
PRMT2α	32.6	Predominantly nuclear, excluding nucleoli	Breast cancer cell lines and tumour samples	[22]
PRMT2β	34	Cytoplasmic and nuclear, including nucleoli	Breast cancer cell lines and tumour samples	[22]
PRMT2γ	25.8	Predominantly nuclear, excluding nucleoli	Breast cancer cell lines and tumour samples	[22]
CARM1/CARM1v1/CARM1FL	66	ND	Breast cancer cell lines	[23,24]
CARM1v2	71	ND	Breast cancer cell lines	[23,24]
CARM1v3	63	ND	Breast cancer cell lines	[23,24]
CARM1v4/CARM1Δ15	64	ND	Breast cancer cell lines	[23,24]
PRMT7α	78	Cytoplasmic and nuclear	ND	[27]
PRMT7β	82	Predominantly cytoplasmic	ND	[27]

ND: Not determined; PRMT: Protein arginine methyltransferase.