PROSITE documentation PDOC00649

MARCKS family signatures

The myristoylated alanine-rich C-kinase substrate (MARCKS) [1] is a protein of about 300 amino acid residues . It is one of the most prominent cellular substrate for protein kinase C (PKC). The N-terminal glycine residue of MARCKS is myristoylated and allows the protein to associate with plasma membranes. MARCKS binds calmodulin in a calcium-dependent manner; the region of MARCKS responsible for calcium-binding is a highly basic domain of 25 amino acids (called PSD) that contains the PKC phosphorylation sites. When it is not phosphorylated, the PSD domain can bind to filamentous actin.

A protein known as MRP (MARCKS-related protein), MacMARKCS or F52 is highly similar to MARCKS both in its properties (myristoylation, phosphorylation, calmodulin-binding) and at the level of the sequence.

We have selected two signature patterns for this family of protein. The first is a perfectly conserved heptapeptide located in the N-terminal part of MARCKS and MRP and also found in the cytoplasmic region of the cation-independent mannose-6-phosphate receptor. The function of this conserved region is not yet known. The second pattern corresponds to the PSD domain.