Table 1.

List of selenoproteins and selenium-incorporating proteins with their functions

Name of protein	Abbreviation	Functions
Glutathione peroxidase 1	GPx1, GPX1	Considered the most important cellular redox regulator [18]
Glutathione peroxidase 2	GPx2, GPX2	Regulates redox homeostasis, essential for peroxide reduction in the gut, involved in tissue regeneration and cell proliferation [18]
Glutathione peroxidase 3	GPx3, GPX3	Regulates redox homeostasis, essential for peroxide reduction in the blood [18]
Glutathione peroxidase 4	GPx4, GPX4	Regulates redox homeostasis, important for phospholipid peroxide reduction [18, 53, 54]
Glutathione peroxidase 6	GPx6, GPX6	Involved redox homeostasis mainly in olfactory epithelium [18, 53, 54]
Iodothyronine deodinase 1	DIO1	Converts T4 to T3, primarily in the thyroid, liver and kidney and regulates the circulating levels of thyroid hormone [18, 53, 54]
Iodothyronine deodinase 2	DIO2	Converts T4 to T3, it is tissue specific (it is abundantly found in the thyroid gland and in the heart) [18, 53, 54]
Iodothyronine deodinase 3	DIO3	Inactivates T4 and T3 [18, 53, 54]
Thioredoxin reductase Type I	TXNRD1, also named: TR1, TrxR1	Reduces oxidized thioredoxin, it functions mainly in the cytosol [18, 53, 54]
Thioredoxin reductase Type II	TRXRD2, also named: TR3	Reduces oxidized thioredoxin, it functions mainly in the mitochondria [18, 53, 54]
Thioredoxin reductase Type III	TRXRD3, also named: TR2,TGR	Reduces oxidized thioredoxin, it is found mainly in the testis [18, 53, 54]
Methionine-R-sulfoxide reductase	MsrB1, SelR, SelX, MSRB1	Reduces oxidized methionine residues on proteins [53, 54], may be involved in inflammation [55]
Selenoprotein F	SELENOF, also named: Sep15	Regulation of redox homeostasis in the ER, may be involved in protein folding regulation [54]
Selenoprotein H	SELENOH, also named, SelH	Not yet fully established functions [54], involved in redox regulation and as a transcription factor [53]
Selenoprotein I	SELENOI, also named Sell, SEPI, EPT1	Not yet fully established functions, may involve in phospholipid biosynthesis [53] [54],
Selenoprotein K	SELENOK, also named: Selk	Involved in immune cell processes, cellular calcium hemostasis as well as mechanisms related to ER stress [53]
Selenoprotein M	SELENOM, also named: SelM, SEPM	Not yet established functions, may be involved in neuroprotection and calcium hemostasis [54], may have roles in body weight and energy metabolism [53]
Selenoprotein N	SELENON, also named: SelN, SepN, SEPN1	Has roles during muscle development [53], involved in calcium hemostasis [56]
Selenoprotein O	SELENOO, also named: SelO	Not yet established functions [54], may have function in redox regulation [53]
Selenoprotein P	SELENOP, also named: SelP, SEPP1	Mainly transports selenium to tissues [18, 53, 54]. May have anti-fibrotic effects [57]
Selenoprotein S	SELENOS, also named: SelS, SEPS1, VIMP	May involve in mechanisms related to ER stress and protection against protein aggregation [53]
Selenoprotein T	SELENOT, also named: SelT	Not yet fully established functions, may have influence on cell structure organization and cell adhesion characteristics [54], involved in calcium mobilization in the ER [53] and in protein folding regulation [58, 59]
Selenoprotein V	SELENOV, also named: SelV	Not yet fully established functions [54], expressed mainly in the testes [53]
Selenoprotein W	SELENOW, also named: SelW, SEPW1	Not yet fully established functions [54], may have roles in antioxidant defense and muscle growth [53]. May stimulate cell cycle progression by facilitating G1/S transition [60]