SRD5A3 siRNA – Polyprenol Reductase (Human)

The protein encoded by this gene belongs to the steroid 5-alpha reductase family, and polyprenol reductase subfamily. It is involved in the production of androgen 5-alpha-dihydrotestosterone (DHT) from testosterone, and maintenance of the androgen-androgen receptor activation pathway. This protein is also necessary for the conversion of polyprenol into dolichol, which is required for the synthesis of dolichol-linked monosaccharides and the oligosaccharide precursor used for N-linked glycosylation of proteins. Mutations in this gene are associated with congenital disorder of glycosylation type Iq. [provided by RefSeq, Mar 2011]

SRD5A3: Probable polyprenol reductase. Plays a key role in early steps of protein N-linked glycosylation by being required for the conversion of polyprenol into dolichol. Dolichols are required for the synthesis of dolichol-linked monosaccharides and the oligosaccharide precursor used for N-glycosylation. Probably acts as a polyprenol reductase that promotes the reduction of the alpha-isoprene unit of polyprenols into dolichols in a NADP- dependent mechanism. Also able to convert testosterone (T) into 5- alpha-dihydrotestosterone (DHT). Defects in SRD5A3 are the cause of congenital disorder of glycosylation type 1Q (CDG1Q). It is a multisystem disorder caused by a defect in glycoprotein biosynthesis and characterized by under-glycosylated serum glycoproteins. Congenital disorders of glycosylation result in a wide variety of clinical features, such as defects in the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency. The broad spectrum of features reflects the critical role of N-glycoproteins during embryonic development, differentiation, and maintenance of cell functions. Defects in SRD5A3 are the cause of Kahrizi syndrome (KHRZ). An autosomal recessive neurodevelopmental disorder characterized by mental retardation, cataracts, coloboma, kyphosis, and coarse facial features. Belongs to the steroid 5-alpha reductase family. Polyprenol reductase subfamily.

Protein type: Lipid Metabolism - androgen and estrogen; Membrane protein, multi-pass; Membrane protein, integral; EC 1.3.1.22; EC 1.3.1.94; Oxidoreductase

Chromosomal Location of Human Ortholog: 4q12

Cellular Component: endoplasmic reticulum membrane; endoplasmic reticulum; integral to membrane

Molecular Function: oxidoreductase activity, acting on the CH-CH group of donors, NAD or NADP as acceptor; cholestenone 5-alpha-reductase activity; 3-oxo-5-alpha-steroid 4-dehydrogenase activity

Biological Process: steroid metabolic process; cellular protein metabolic process; dolichol-linked oligosaccharide biosynthetic process; dolichyl diphosphate biosynthetic process; dolichol metabolic process; protein amino acid N-linked glycosylation via asparagine; androgen biosynthetic process; polyprenol catabolic process; post-translational protein modification

Disease: Congenital Disorder Of Glycosylation, Type Iq; Kahrizi Syndrome