Isolation of a cDNA encoding the human G_M2 activator protein

Abstract

The Gr,,r activator protein is a glycolipid-binding protein required for the lysosomal degradation of ganglioside Gi,,r. A human fibroblast cDNA library was screened with mixtures of oligonucleotide probes corresponding to four different areas of the amino acid sequence. A putative clone (821 bp) which gave positive signals to all four probe mixtures was purified and sequenced. The sequence was colinear with the sequence of 160 amino acids of the mature GMZ activator protein. Availability of the cDNA clone should facilitate investigation into function of the GM* activator protein and also into genetic abnormalities underlying GM2 gangliosidosis AB variant.GM2 activator protein; GM2 gangliosidosis; cDNA sequence

The complete amino‐acid sequences of human ganglioside GM2 activator protein and cerebroside sulfate activator protein

“…Furthermore, a methionine residue near the C-terminus is strongly suggested by the successful coupling of peptide BG4 to aminopropyl glass via a terminal homoserine lactone. This is noteworthy, because the cDNA sequence of GM2 activator revealed glycine and isoleucine at the C-terminus [24]. Since simple sequencing errors cannot account for the replacement of Met-Ser by Gly-Ile and no cDNA clone has been found up to now corresponding to the protein data, this discrepancy cannot be resolved at the moment.…”

Cloning and sequence analysis of a cDNA clone coding for the mouse GM2 activator protein

“…Screening the mouse macrophage cDNA library A total of 1 x 106 plaques from the mouse macrophage cDNA library were screened using a 0.8 kb human GM2 activator protein cDNA, pGAP1 (Schroder et al, 1989), as a probe. Twenty positive plaques were identified and the longest cDNA insert in these (1.1 kb) was selected for characterization and sequencing.…”

“…Isolation of cDNA clones containing the complete coding sequence of the human GM2 activator protein has previously presented difficulties that may stem from the low abundance of mRNA (Schroder et al, 1989;Xie et al, 1991;Nagarajian et al, 1992). We were somewhat surprised to find a relatively high number of positive plaques when screening the mouse macrophage library, and to isolate one containing the whole coding sequence, although it was incomplete at the 3' end.…”

“…cDNAs encoding the human GM2 activator protein have been isolated and sequenced (Schroder et al, 1989;Xie et al, 1991;Nagarajian et al, 1992), the protein sequence has been determined independently (Furst et al, 1990) and the exon-intron organization of the gene determined (Klima et al, 1991). A processed GM2 activator pseudogene is located on chromosome 3 (Xie et al, 1992a).…”

Effect of structural modifications of ganglioside GM2 on intra-molecular carbohydrate-to-carbohydrate interaction and enzymatic susceptibility

“…The clinical importance of GM2AP was revealed by the findings that this activator protein was absent in variant AB TSD [8][9][10]. To understand the catabolism of GM2 and the pathogenesis of TSD, the molecular cloning of the gene encoding GM2AP [11][12][13] and its expression [14,15], as well as the targeted disruption of this gene in mice [16], played center stage of TSD associated research during the late 20th century. Although the crystal structure of GM2AP has been solved [17], the mechanism of action of this protein cofactor is still not well understood.…”