. 2022 Jan 8;27(2):392. doi: 10.3390/molecules27020392

Table 1.

Selenoprotein classified by cellular function and effects on health [29,61,84,85,86,87,88,89,90].

Selenoprotein	Subcellular Location	Function	Effect on Health and Disease	Ref.
Glutathione Peroxidases (GPxs)
GPx 1	Cytoplasm Mitochondrial membrane	Antioxidant. Cellular H₂O₂ ↓and lipid peroxide ↓. Cardioprotective and anti-angiogenic.	Cardiovascular: CVD, hypertension, peripheral vascular disease, ICH. Cancer: lung, prostate, bladder, primary liver Keshan disease, Kashin–Beck disease.	[91,92,93,94,95,96]
GPx2	Cytoplasm	Antioxidant. Peroxide ↓ in the gut. Carcinogenesis.
GPx3	Secreted abundantly in plasma	Antioxidant. Peroxide ↓ in blood. Tumor suppressor.	Ischemic stroke, differentiated thyroid cancer.	[97,98]
GPx4	Cytoplasm Mitochondria Nuclei	Antioxidant. Phospholipid peroxide ↓. Regulation of ferroptosis and phospholipid, H₂O₂ levels. Involved in spermiogenesis.	Adenomatous polyps, male infertility. Cancer: colorectal cancer, breast cancer.	[99,100]
GPx6	Secreted protein	Cellular H₂O₂ ↓ in the olfactory epithelium.	-
Iodothyronine Deiodinases (DIOs)
DIO1	Plasma membrane	Regulation of systemic circulating thyroid hormone levels.	Muscle strength, lean body mass. Cardiovascular diseases.	[101]
DIO2	ER membrane	Regulation of local muscular thyroid hormone levels.	Type-2 diabetes and insulin resistance. Osteoporosis and osteoarthritis. Mental retardation.	[102,103,104,105]
DIO3	Plasma membrane	Inactivates thyroid hormone.	Osteoporosis and osteoarthritis.	[106]
Thioredoxin Reductases (TrxRs)
TrxR1	Cytoplasm Nucleoplasm	Antioxidant. Regenerates reduced thioredoxin. Embryonic development.	Advanced colorectal adenoma.	[107]
TrxR2	Mitochondrial membrane	Antioxidant. Catalyzes a variety of reactions, specific for Trx and GPx. Embryonic development.	Gastric cancer.	[108]
TrxR3	Cytoplasm Nucleoplasm	Antioxidant. Oxidized ↓ of Trx and GPx2. Involved in spermiogenesis.	-
Selenoprotein P (SEPP)	Secreted protein	Selenium transport to peripheral tissues.	Prostate cancer, colorectal adenoma, colorectal cancer. Neurological disorders, type 2 diabetes.	[100,107,109,110]
Selenoprotein M (SELENOM)	ER membrane	Protein folding in ER. Involved in redox regulation.	Neurological disorders.
Selenoprotein N (SELENON)	ER membrane	Regulation of muscle development.	Muscle disorders.	[111,112]
Selenoprotein O (SELENOO)	Mitochondrial membrane	Possibly involved in redox regulation.	-
Selenoprotein S (SELENOS)	ER membrane	Involved in ER-associated degradation and immune response. Involved in protein folding.	Cardiovascular disease. Cancer: gastric, colorectal, and rectal cancer. Inflammatory response. Pre-eclampsia.	[100,113,114,115]
Selenoprotein T (SELENOT)	ER membrane Golgi-complex	Involved in redox regulation and cell anchorage.	-
Selenoprotein V (SELENOV)	Unclear	Unknown.	-
Selenophosphate synthetase 2 (SEPHS2)	Nucleoplasm	Synthesis of selenophosphate.	-
MSRB1 Selenoprotein R (SELENOR)	Cytoplasm Nucleoplasm	Antioxidant. Regulation of actin polymerization. Involved in redox regulation.	Cardiovascular diseases.
Selenoprotein W (SELENOW)	ER membrane	Antioxidant. Involved in muscle growth and differentiation. Involved in redox regulation.	Muscle disorders, neurological disorders.
Selenoprotein H (SELENOH)	Nucleoplasm and nucleoli	Antioxidant. Involved in redox regulation.	Neurological disorders.
Selenoprotein I (SELENOI)	Plasma membrane	Involved in phospholipid biosynthesis. Involved in protein folding.	-
Selenoprotein F (SELENOF)	ER membrane	Involved in protein folding. Possibly implicated in cancer etiology.	Cancer: Prostate cancer, lung cancer, and rectal cancer.	[113,116,117]
Selenoprotein K (SELENOK)	ER membrane	Modulates calcium metabolism. Involved in ER-associated degradation and immune response.	-

Abbreviations: ER: endoplasmic reticulum; MSRB1: methionine sulfoxide reductase B1; H₂O₂: hydrogen peroxide; BAT: brown adipose tissue; ICH: intracerebral hemorrhage; ↓: reduced or decreased.