A Glutamine to Proline Exchange at Amino Acid Residue 1098 in Sucrase Causes a Temperature-sensitive Arrest of Sucrase-isomaltase in the Endoplasmic Reticulum andcis-Golgi

摘要: A striking feature of phenotype II in congenital sucrase-isomaltase deficiency is the retention brush border protein (SI) cis-Golgi. This transport block consequence a glutamine to proline substitution at amino acid residue 1098 sucrase subunit. Here we provide unequivocal biochemical and confocal data show that SIQ/P mutant reveals characteristics temperature-sensitive mutant. Thus, correct folding, competent intracellular transport, full enzymatic activity can be partially restored by expression permissive temperature 20 °C instead 37 °C. The acquisition normal trafficking function appears utilize several cycles anterograde retrograde steps between endoplasmic reticulum Golgi implicating molecular chaperones calnexin heavy chain-binding protein. presented this communication are our knowledge first implicate mutation an intestinal enzyme or disorder.