The expression of a major cellular substrate for protein kinase C, the MARCKS protein, is regulated in a cell-, tissue-, and developmental stage-specific fashion, in addition, this expression can be stimulated acutely by various cytokines in certain cell types (1). MARCKS) binds calmodulin and is a predominant, specific substrate of PKC which is phosphorylated during macrophage and neutrophil activation, growth factor-dependent mitogenesis and neurosecretion, it is redistributed from plasma membrane to cytoplasm when phosphorylated and is involved in leukocyte motility. It has been reported that MARCKS is a filamentous (F) actin crosslinking protein, with activity that is inhibited by PKC-mediated phosphorylation and by binding to calcium-calmodulin. MARCKS may be a regulated crossbridge between actin and the plasma membrane, and modulation of the actin crosslinking activity of the MARCKS protein by calmodulin and phosphorylation represents a potential convergence of the calcium-calmodulin and PKC signal transduction pathways in the regulation of the actin cytoskeleton (2).