A conserved hydrophobic tetrad near the C terminus of the secretory Na+-K+-2Cl- cotransporter (NKCC1) is required for its correct intracellular processing.

ABSTRACT: Little is known about the intracellular folding and trafficking of integral membrane proteins. Here we identify a hydrophobic amino acid tetrad (ILLV) close to the C terminus of the secretory Na+-K+-2Cl- cotransporter (NKCC1) that is important for the proper intracellular processing of this protein. This tetrad appears in a C-terminal sequence pattern that is conserved across species in a number of members of the NKCC1 gene family (slc12) of electroneutral salt transporters. We studied the effects of various mutations of these amino acids on NKCC1 transiently transfected into HEK-293 cells. Our results show that mutation of two of these residues to alanine leads to a >50% reduction in expression and complex glycosylation levels and that multiple mutations to alanine have cumulative effects

SUBMITTER: Nezu A 

PROVIDER: S-EPMC2652323 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature