N-acetylglucosamine-1-phosphate transferase

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N-acetylglucosamine-1-phosphate transferase, alpha and beta subunits
Identifiers
SymbolGNPTAB
Alt. symbolsGNPTA
Entrez79158
HUGO29670
OMIM607840
RefSeqNM_024312
UniProtQ3T906
Other data
LocusChr. 12 q23.3
N-acetylglucosamine-1-phosphate transferase, gamma subunit
Identifiers
SymbolGNPTG
Alt. symbolsGNPTAG
Entrez84572
HUGO23026
OMIM607838
RefSeqNM_032520
UniProtQ9UJJ9
Other data
LocusChr. 16 p13.3

N-acetylglucosamine-1-phosphate transferase is a transferase enzyme.

Function

It is made up of two alpha (α), two beta (β), and two gamma (γ) subunits. GNPTAB produces the alpha and beta subunits, GNPTG produces the gamma subunit. GlcNAc-1-phosphotransferase functions to prepare newly made enzymes for lysosome transportation (lysosomal hydrolases to the lysosome). Lysosomes, a part of an animal cells, helps break down large molecules into smaller ones that can be reused. GlcNAc-1-phosphotransferase catalyzes the N-linked glycosylation of asparagine residues with a molecule called mannose-6-phosphate (M6P). M6P acts as indicator whether a hydrolase should be transported to the lysosome or not. Once a hydrolase has the indication from an M6P, it can be transported to a lysosome. Surprisingly some lyosomal enzyme are only tagged at a rate of 5% or lower.

Clinical significance

It is associated with the following conditions:[1][2]

In melanocytic cells GNPTG gene expression may be regulated by MITF.[3]

References

  1. Online Mendelian Inheritance in Man (OMIM) MUCOLIPIDOSIS II ALPHA/BETA -252500
  2. Online Mendelian Inheritance in Man (OMIM) MUCOLIPIDOSIS III GAMMA -252605
  3. Hoek KS, Schlegel NC, Eichhoff OM, et al. (2008). "Novel MITF targets identified using a two-step DNA microarray strategy". Pigment Cell Melanoma Res. 21 (6): 665–76. doi:10.1111/j.1755-148X.2008.00505.x. PMID 19067971.

Kang, C., Riazuddin, S., Mundorff, J., Krasnewich, D., Friedman, P., Mullikin, J.C., and Drayna, D. (2010). Mutations in the Lysosomal Enzyme–Targeting Pathway and Persistent Stuttering. New England Journal of Medicine 362, 677-685.

External links