Mammalian enabled (Mena) is a member of a protein family thought to link signal transduction pathways to localized remodeling of the actin cytoskeleton. Mena binds directly to Profilin, an actin-binding protein that modulates actin polymerization. In primary neurons, Mena is concentrated at the tips of growth cone filopodia. Mena-deficient mice are viable; however, axons projecting from interhemispheric cortico-cortical neurons are misrouted in early neonates, and failed decussation of the corpus callosum as well as defects in the hippocampal commissure and the pontocerebellar pathway are evident in the adult. Mena-deficient mice that are heterozygous for a Profilin I deletion die in utero and display defects in neurulation, demonstrating an important functional role for Mena in regulation of the actin cytoskeleton.
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We gratefully acknowledge Pieter Dikkes, William Perry, and Christine Canida for expert technical assistance and Drs. Reinhard Fässler, Anthony Koleske, David Van Vactor, and members of the Gertler lab for critical reading of the manuscript. We thank Drs. Peter L. Woodhams and Mike Webb for the gift of the Py antibody, Drs. Gretchen Snyder and Angus Nairn for the DARPP32 antibody, and Dr. Frank Solomon for gift of the 13H9 antibody. L. M. L. is supported by a fellowship from the Anna Fuller Foundation, and M. A. G. is a Medical Foundation Research fellow with funding through the June Rockwell Levy Foundation; additional support was provided by NIH grants HD28478 and MR Center grant HD18655 (to J. D. M.), GM53236 (to D. J. K.), and HD24875 and HD25326 (to P. S.). This research was supported by grants from Merck and Co. and the Medical Foundation and by NIH grant GM58801 (to F. B. G.).