This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This program aims to determine the structures of proteins involved in cell membrane targeting, adhesion, and signaling, in order to establish the mechanism and specificity of their interactions. There are currently two projects with crystals that require synchrotron radiation. 1. Structure of full-length a-catenin, an F-actin binding protein that couples cadherin-based cell adhesion to regulation of the actin cytoskeleton. 2. Complexes of the SNARE regulator Munc18a bound to mutants of the SNARE syntaxin that will allow understanding of allosteric regulation of this interaction.