Protein fatty acylation: a novel mechanism for association of proteins with membranes and its role in transmembrane regulatory pathways

A wide range of proteins of cellular and viral origin have been shown to be modified covalently by long-chain fatty acids. Recent studies have revealed at least two distinct types of protein fatty acylation which involve different fatty acyltransferases. The abundant fatty acid, palmitate, is incorporated post-translationally through a thiol ester linkage into a variety of cell surface glycoproteins and non-glycosylated intracellular proteins. In contrast, the rare fatty acid, myristate, is incorporated co-translationally through an amide linkage into numerous intracellular proteins. Identification of proteins that contain covalent fatty acids has revealed that this modification is common to a broad array of proteins that play important roles in transmembrane regulatory pathways. For many of these proteins, the fatty acid moiety appears to play an important role in directing the polypeptide to the appropriate membrane and in mediating protein-protein interactions within the membrane. This review will summarize recent studies that define different pathways for protein fatty acylation and will consider the potential functions for this unique covalent modification of proteins.