Actin-based cytoskeleton in growth cone activity

A growing tip of neurite, the neuronal growth cone, is a highly motile and adhesive form of cytoarchitecture. The growth cone plays vital roles for navigation, elongation and maintenance of neurites. One major constituent of growth cones, regulated by the intracellular Ca2+ signal, is the actin-based cytoskeleton. In this article, I have summarized four types of Ca(2+)-dependent regulation of the actin-based cytoskeleton in growth cones: gelsolin-actin, myosin II-actin microfilament, myosin II-actin, and Ca(2+)-sensitive alpha-actinin-actin systems. The four examples of Ca(2+)-dependent regulation described here may be involved in growth cone motility. The actin-based membrane skeleton forming a meshwork beneath the cytoplasmic surface of the growth cone membrane is also important for adhesion of growth cones to recognize cue molecules. The actin-based membrane skeleton participates in this recognition process and the adhesion-dependent signal transduction in association with receptors for cell adhesion molecules.