type1 (*601786, 22q13.2) and type2 (*601785; 16p13.7)
Function
Involved in the synthesis of the GDP-mannose and dolichol-phosphate-mannose required for a number of critical mannosyl transfer reactions By similarity.
Catalytic activity
Alpha-D-mannose 1-phosphate = D-mannose 6-phosphate.
Pathway
Nucleotide-sugar biosynthesis; GDP-alpha-D-mannose biosynthesis; alpha-D-mannose 1-phosphate from D-fructose 6-phosphate: step 2/2.
Subunit structure
Homodimer By similarity.
Subcellular location
Cytoplasm.
Involvement in disease
Defects in PMM2 are the cause of congenital disorder of glycosylation type 1A (CDG1A) [MIM:212065]; also known as carbohydrate-deficient glycoprotein syndrome type Ia (CDGS1A) or Jaeken syndrome. Congenital disorders of glycosylation are metabolic deficiencies in glycoprotein biosynthesis that usually cause severe mental and psychomotor retardation. They are characterized by under-glycosylated serum glycoproteins. CDG1A is an autosomal recessive disorder characterized by a severe encephalopathy with axial hypotonia, abnormal eye movement, and pronounced psychomotor retardation, as well as peripheral neuropathy, cerebellar hypoplasia, and retinitis pigmentosa. Patients show a peculiar distribution of subcutaneous fat, nipple retraction, and hypogonadism. Ref.1 Ref.12 Ref.13 Ref.14 Ref.15 Ref.16 Ref.17 Ref.18 Ref.19 Ref.20 Ref.21 Ref.22 Ref.23
Sequence similarities
Belongs to the eukaryotic PMM family.
Biophysicochemical properties
Kinetic parameters:
KM=16 µM for alpha-D-mannose 1-phosphate Ref.7
KM=13.5 µM for alpha-D-glucose 1-phosphate
