Editorials |
From the Puget Sound Blood Center and Division of Hematology, Department of Medicine, University of Washington, Seattle.
Correspondence to José A. López, Puget Sound Blood Center, Research Division, 921 Terry Avenue, Seattle, WA 98104-1256. E-mail josel@psbc.org
An extract of the first 250 words of the full text is provided, because this article has no abstract. |
Posttranslational modification of proteins is the foundation of intracellular signaling. Without the ability to reversibly modify proteins and lipids, cells would be unable to react to signals received from their environment. Posttranslational modification of proteins usually, but not always, occurs after a protein has arrived at the appropriate subcellular location. In certain instances, however, such modifications serve as addresses to correctly target the protein within the cell.
See page 1478
Phosphorylation is the most widely studied of the posttranslational modifications. Both proteins and lipids can be reversibly phosphorylated, with the modification thereby being able to act as an on/off switch for the propagation of intracellular signals. Proteins can also be modified by attachment of lipid moieties (lipidation), modifications which have in recent years gained attention for their significant roles in propagating intracellular signals.
Lipid modifications of proteins fall into several categories, of which 4 are predominant: (1) N-myristoylation, where myristate (C14) is cotranslationally attached to proteins at N-terminal glycine residues13; (2) Addition of glycosyl phosphatidylinositol (GPI) anchors, where GPI is attached to the C termini of proteins4; (3) S-prenylation, where a farnesyl (C15) or geranylgeranyl (C20) moiety is attached to a C-terminal cysteine within a CAAX motif (where C is cysteine, A is an aliphatic amino acid, and X is any amino acid)5; and (4) S-acylation (also known as S-palmitoylation) where palmitate (C16) and, less frequently, other fatty acids are attached to cysteine residues.6,7
Of the known membrane-targeting lipid modifications, palmitoylation is unique
Related Article:
Arterioscler Thromb Vasc Biol 2007 27: 1478-1485.
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