Manifold reduction of moesin in fetal Down syndrome brain

Moesin is a member of the ERM family and is involved in plasma membrane-act in cytoskeleton crosslinking, resulting cell adhesion, shape, and motility. Because moesin was shown to be highly expressed in growth cones and moesin /radixin suppression led to impaired structure and function of this key ele ment in brain development, we tested the ERM family, ezrin, radixin, and mo esin, in fetal Down syndrome (DS) cortex at the early second trimester. We applied two-dimensional gel electrophoresis with subsequent MALDI detection and identification of protein spots followed by quantification with specif ic software. Moesin was shown to be significantly and manifold reduced in f etal DS brain, whereas reduction of ezrin and radixin did not reach statist ical significance. We therefore propose the involvement of moesin in develo pmental impairment of DS brain, including deteriorated arborisation, neurit ic outgrowth, and neuronal migration. Furthermore, decreased moesin is the second F-actin bundling protein, besides drebrin, that is manifold reduced in fetal DS brain. (C) 2001 Academic Press.