MARCKS protein regulation of human neutrophil migration in vitro

Abstract

Protein kinase C is required for neutrophil migration as is the regulatory molecule calmodulin. The actin binding protein Myristoylated Alanine‐Rich C‐kinase Substrate (MARCKS), which is phosphorylated by PKC and binds calmodulin, is a potential point of convergence of these two regulatory mechanisms. Stimulation of neutrophils with the chemoattractant peptide fMLF results in rapid MARCKS phosphorylation and dissociation from the cell membrane. The hypothesis that MARCKS has a role in the regulation of neutrophil migration was tested using a myristoylated peptide corresponding to the first 24 amino acids of the MARCKS aminoterminus (MANS peptide). Treatment of isolated human neutrophils with MANS (50 μM) significantly inhibited their migration and beta 2 integrin dependent adhesion in response to fMLF, IL8, or LTB4. A missense peptide (RNS peptide) did not affect migration or adhesion. MANS significantly reduced F‐actin content in neutrophils 30s after fMLF stimulation, although the peptide did not alter the ability of cells to organize the actin cytoskeleton or spread. MANS did not alter fMLF stimulated increase in surface expression of beta 2 integrins. Our data suggest that MARCKS, via its myristoylated aminoterminus, is a key regulator of neutrophil migration and adhesion. Supported by NIH R37 HL36982 and the NC State Center for Comparative Medicine and Translational Research.