ALG9
Function
Mannosyltransferase that operates in the biosynthetic pathway of dolichol-linked oligosaccharides, the glycan precursors employed in protein asparagine (N)-glycosylation. The assembly of dolichol-linked oligosaccharides begins on the cytosolic side of the endoplasmic reticulum membrane and finishes in its lumen. The sequential addition of sugars to dolichol pyrophosphate produces dolichol-linked oligosaccharides containing fourteen sugars, including two GlcNAcs, nine mannoses and three glucoses. Once assembled, the oligosaccharide is transferred from the lipid to nascent proteins by oligosaccharyltransferases. In the lumen of the endoplasmic reticulum, catalyzes the addition of the seventh and ninth alpha-1,2-linked mannose residues to Man(6)GlcNAc(2)-PP-dolichol and Man(8)GlcNAc(2)-PP-dolichol respectively.
Involvement in disease
A chromosomal aberration involving ALG9 is found in a family with bipolar affective disorder. Translocation t(9;11)(p24;q23). However, common variations in ALG9 do not play a major role in predisposition to bipolar affective disorder.
Congenital disorder of glycosylation 1L
CDG1L
A form of congenital disorder of glycosylation, 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.
None
The disease is caused by variants affecting the gene represented in this entry.
Gillessen-Kaesbach-Nishimura syndrome
GIKANIS
A rare autosomal recessive syndrome characterized by severe skeletal dysplasia, facial dysmorphic features, polycystic kidney disease and other visceral malformations. It may be lethal in utero or early in life. The skeletal features uniformly comprise a round pelvis, mesomelic shortening of the upper limbs and defective ossification of the cervical spine.
None
The disease is caused by variants affecting the gene represented in this entry.
Pathway
Protein modification; protein glycosylation.
Sequence Similarities
Belongs to the glycosyltransferase 22 family.
Tissue Specificity
Ubiquitously expressed; with highest levels in heart, liver and pancreas.
Cellular localization
- Endoplasmic reticulum membrane
- Multi-pass membrane protein
Alternative names
DIBD1, ALG9, Asparagine-linked glycosylation protein 9 homolog, Disrupted in bipolar disorder protein 1