Abstract
Microglia are resident macrophages in the central nervous system. In response to injuries or inflammation, microglia are stimulated to exhibit drastic changes in morphology and functions, and called as "activated microglia". Activated microglia proliferate vigorously, migrate and accumulate to the site of the inflammation, and phagocytose pathogens and cellular debris. Further, activated microglia produce various bioactive molecules to assist repair and regeneration of the nervous system. In this report, to elucidate molecular mechanisms of microglia activation, we focused on signaling molecules including small G protein Rac and microglia-specific calcium binding protein Iba1. Activated microglia exhibit extremely active motility and phagocytosis, suggesting the existence of microglia-specific mechanisms regulating the actin cytoskeleton. We previously reported that expression of Iba1 is upregulated during microglia activation, and that Iba1 is involved in motility and phagocytosis of microglia. Furthermore, Iba1 was shown to be cooperating with Rac in regulation of the actin cytoskeleton. Herein, we demonstrated intracellular behavior of these signaling molecules in microglia activation. [J Physiol Sci. 2006;56 Suppl:S214]
