F. Wohnsland et al., Influence of the effector peptide of MARCKS-related protein on actin polymerization: a kinetic analysis, BIOPHYS CH, 85(2-3), 2000, pp. 169-177
The members of the MARCKS protein family, MARCKS (an acronym for myristoyla
ted alanine-rich C kinase substrate) and MARCKS-related protein (MRP), inte
ract with membranes, protein kinase C, and calmodulin via their effector do
main, a highly basic segment composed of 24-25 amino acid residues. This do
main is also involved in the interaction between MARCKS/MRP and actin. In t
his article we show that a peptide corresponding to the effector domain of
MRP, the effector peptide, strongly influences the dynamics of actin polyme
rization. Depending on the stoichiometric ratio of effector peptide to acti
n the peptide either accelerates or retards the actin polymerization proces
s, which takes place in the presence of near-physiological salt concentrati
ons. A model is developed in which this phenomenon is explained by two inde
pendent nucleation processes involving free actin monomers and peptide-boun
d actin monomers, respectively. As a control, a possible regulatory mechani
sm has been investigated: we show that calmodulin inhibits the actin polyme
rizing activity of the MRP effector peptide, thereby validating our model a
pproach. (C) 2000 Elsevier Science B.V. All rights reserved.