ganglioside GM2 activator; GM2-AP; cerebroside sulfate activator protein; shingolipid activator protein 3; SAP-3; contains: ganglioside GM2 activator isoform short (GM2A)

Function

• binds gangliosides & stimulates ganglioside GM2 degradation
• Stimulates only the breakdown of ganglioside GM2 & glycolipid GA2 by beta-hexosaminidase A
• extracts single GM2 molecules from membranes & presents them in soluble form to beta-hexosaminidase A for cleavage of N-acetyl-D-galactosamine & conversion to GM3

Structure

• the Ser in positions 32 & 33 are absent in 80% of the sequenced protein

Compartment

lysosome

Pathology

• defects in GM2A are the cause of Tay-sachs disease AB variant

More general terms

• glycoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=2760
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:2760
• OMIM: https://mirror.omim.org/entry/272750
• UniProt: http://www.uniprot.org/uniprot/P17900.html