The myristoylated, alanine-rich protein MARCKS is a widely expressed, prominent substrate for protein kinase C, a key enzyme of intracellular signal transduction. The predicted 200-amino acid protein, which they called F52, shares 52% amino acid identity with bovine MARCKS. The similarity between the 2 proteins is found in the consensus myristoylation sequence near the N-terminus and in the 25-amino acid protein kinase C phosphorylation site domain. F52 has a similar amino acid composition to MARCKS, although its alanine content is not as high. It is distributed throughout the mouse brain in a pattern that is distinct from that of MARCKS.A transgene containing this 433-bp fragment from mouse linked to a reporter Mrp beta-galactosidase gene produced normal patterns of Mrp expression in the developing mouse embryo.