lipidated

Lipidated is an adjective used to describe proteins or peptides that have undergone lipidation, a post-translational modification in which one or more lipid groups are covalently attached. Lipidation increases a protein’s hydrophobicity and often promotes association with cellular membranes, while also influencing localization, stability, conformation, and interactions with other proteins.

The main forms of lipidation include:

- N-myristoylation: addition of a myristoyl (14-carbon) group to the amino terminus of a protein, typically catalyzed by N-myristoyltransferases. This modification often facilitates membrane targeting and protein–protein interactions.

- S-palmitoylation: reversible attachment of a palmitoyl (16-carbon) group to cysteine residues via a thioester linkage, carried out by DHHC family palmitoyltransferases. Palmitoylation can regulate trafficking and signaling and is often dynamic.

- Prenylation: attachment of isoprenoid groups (farnesyl or geranylgeranyl) to a cysteine near the C-terminus, mediated by farnesyltransferase or geranylgeranyltransferase. This often aids membrane association and protein localization, notably for certain signaling proteins.

- GPI anchoring: addition of a glycosylphosphatidylinositol anchor at a protein’s C-terminus, covalently tethering the protein to the outer leaflet of the plasma membrane.

Biological roles of lipidation include directing subcellular localization, modulating signaling pathways, and affecting protein stability. Examples include myristoylated Src family kinases, farnesylated Ras proteins, and many GPI-anchored enzymes. Lipidation can be a dynamic and reversible process (notably palmitoylation), enabling rapid regulation of protein function. Dysregulation of lipidation pathways is implicated in cancer, infectious diseases, and other conditions, and therapeutic strategies have targeted prenyltransferases and related enzymes with varying success.