This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Actin and PP1 epitomize the concept of protein multifunctionality. Actin interacts with hundreds of proteins that mediate its function in motile and morphogenetic processes. PP1 interacts with over a hundred regulatory subunits, which determine its substrate specificity and sub-cellular localization. The general goal of our research is to elucidate basic principles that govern protein-protein interactions in these two systems and their role in the regulation of cellular processes. X-ray beamtime is requested to determine a number of relevant structures for which crystals are already available: 1) Structures of the two actin-binding domains of missing in metastasis (MIM), a metastasis suppressor and cytoskeleton regulator protein. We have crystallized the dimer formed by the N-terminal ~250 amino acids of MIM (known as IMD). This domain constitutes a novel actin bundling/filopodium-forming actin-binding domain. We have also crystallized a complex of actin with the WASP-homology domain 2 (WH2) located at the C-terminus of MIM. This research will involve Se-Met MAD-phasing and high-resolution data collection experiments. 2) Structures of complexes of actin with the WH2 domains of 10 representative cytoskeletal proteins, including VASP, Thymosin beta 4, and WASP. High-resolution structural information is absolutely necessary in this case to understand the striking functional diversity characteristic of this widespread actin-binding motif. The structures will be determined by molecular replacement. 3) Structures of monofilin and the complex of monofilin-actin. We call monofilin the C-terminal ADF domain of twinfilin, a protein composed of tamden ADF motifs. ADF-H is a widespread ~150 amino acid motif, which plays a key role in F-actin disassembly and treadmilling. 4) Structure of a complex between glycogen phosphorylase a and a target peptide from the liver glycogen subunit GL, a regulatory subunit of PP1. This structure is a target for drugs to treat type 2 diabetes
Showing the most recent 10 out of 120 publications
