THE MYRISTOYL-ELECTROSTATIC SWITCH - A MODULATOR OF REVERSIBLE PROTEIN-MEMBRANE INTERACTIONS

Hydrophobic insertion of the acyl chain into the bilayer is necessary but not sufficient for the membrane binding of a myristoylated protein , The myristoylated alanine-rich C kinase substrate (MARCKS), Src, ADP -ribosylation factor and human immunodeficiency virus-1 matrix protein s also contain a cluster of basic residues that bind to acidic phospho lipids; the hydrophobic and electrostatic interactions act together to anchor the protein to a membrane. For MARCKS, and perhaps other prote ins, phosphorylation of serines within its basic cluster reduces the e lectrostatic attraction, producing translocation of the protein from t he membrane to the cytosol by a simple 'electrostatic switch' mechanis m.