MARCKS is the most prominent cellular substrate for protein kinase C. This protein binds calmodulin, actin, and synapsin. MARCKS is a filamentous (F) actin cross-linking protein. Brain, spleen, less in kidney and heart, and very low levels in liver. By lipopolysaccharides (LPS). Phosphorylation by PKC displaces MARCKS from the membrane. It also inhibits the F-actin cross-linking activity. Belongs to the MARCKS family.