The presence of cysteine in the cytoplasmic domain of the vesicular stomatitis virus glycoprotein is required for palmitate addition.

Abstract

The transmembrane glycoprotein (G protein) of vesicular stomatitis virus (VSV) is known to contain 1-2 mol of covalently linked fatty acid (pamitate)/mol of protein. G protein is oriented in cellular membranes such that the carboxyl-terminal 29 amino acids protrude into the cytoplasm. Expression in eukaryotic [African green monkey kidney]cells of mutagenized c[complementary]DNA clones that encode VSV G proteins lacking portions of this cytoplasmic domain was obtained. Labeling of these truncated proteins with [3H]palmitate indicated that the palmitate might be linked to an amino acid residue within the first 14 residues on the carboxyl-terminal side of the transmembrane domain. Using oligonucleotide directed mutagenesis, the single codon specifying cysteine in this domain was changed to a codon specifying serine. Expression of this mutant gene results in synthesis of a G protein lacking palmitate. Evidently, linkage of palmitate to G protein is through the cysteine in the cytoplasmic domain, and such a linkage may occur in many viral and cellular glycoproteins. The G protein lacking palmitate is glycosylated and is transported normally to the cell surface.