SEQUENCE OF A PUTATIVE GLUCOSE-6-PHOSPHATE TRANSLOCASE, MUTATED IN GLYCOGEN-STORAGE-DISEASE TYPE IB

We report the sequence of a human cDNA that encodes a 46 kDa transmemb rane protein homologous to bacterial transporters for phosphate esters . This protein presents at its carboxy terminus the consensus motif fo r retention in the endoplasmic reticulum. Northern blots of rat tissue s indicate that the corresponding mRNA is mostly expressed in liver an d kidney. In two patients with glycogen storage disease type Ib, mutat ions were observed that either replaced a conserved Gly to Cys or intr oduced a premature stop codon. The encoded protein is therefore most l ikely the glucose 6-phosphate translocase that is functionally associa ted with glucose-6-phosphatase. (C) 1997 Federation of European Bioche mical Societies.