Palladin is a novel 92 kD protein that appears to play a critical role in the assembly of actin-based structural arrays. We hypothesize that palladin is a key scaffold protein that provides docking sites for multiple proteins that regulate the assembly and higher-order organization of actin filaments. Since the actin cytoskeleton provides the structural framework for many fundamental cellular processes (including spreading, adhesion, and migration), it is important to understand exactly how palladin functions to modulate cytoskeletal organization. To this end, the following questions will be addressed: (1) What are the structural and regulatory proteins of the cytoskeleton that bind to palladin? For these studies, we will be guided by sequence homologies that are shared between palladin and known cytoskeletal proteins, to direct us to potential binding partners. (2) How is palladin regulated? To answer this question, we will take advantage of the observation that palladin becomes modified when cells round up to enter mitosis. We will investigate the biochemical nature of this modification, and we will explore how mitosis-specific modifications of palladin impact upon its ability to bind to its usual partners. (3) What domains of palladin are required for its binding interactions? Docking sites on palladin will be mapped to specific amino acids, so that we can design palladin mutants that are deficient in the ability to provide certain binding sites. These palladin mutants will then be expressed in living cells, to explore the effects on cytoskeletal assembly. In summary, we believe that palladin is a unique and powerful tool with which to study the cellular mechanisms that govern how the cytoskeleton is assembled, maintained and regulated in living cells. Cell spreading, adhesion and migration are critical for processes such as wound healing, inflammation reaction, neurite outgrowth and cancer metastasis; thus, a better understanding of the regulation of actin-based structures could have potential health benefits in many different fields.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM061743-01A2
Application #
6436806
Study Section
Pathobiochemistry Study Section (PBC)
Program Officer
Deatherage, James F
Project Start
2002-04-01
Project End
2006-03-31
Budget Start
2002-04-01
Budget End
2003-03-31
Support Year
1
Fiscal Year
2002
Total Cost
$270,798
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Physiology
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Goicoechea, S M; Bednarski, B; GarcĂ­a-Mata, R et al. (2009) Palladin contributes to invasive motility in human breast cancer cells. Oncogene 28:587-98
Dixon, Richard D S; Arneman, Daniel K; Rachlin, Andrew S et al. (2008) Palladin is an actin cross-linking protein that uses immunoglobulin-like domains to bind filamentous actin. J Biol Chem 283:6222-31
Ronty, Mikko; Taivainen, Anu; Heiska, Leena et al. (2007) Palladin interacts with SH3 domains of SPIN90 and Src and is required for Src-induced cytoskeletal remodeling. Exp Cell Res 313:2575-85
Wall, Michelle E; Rachlin, Andrew; Otey, Carol A et al. (2007) Human adipose-derived adult stem cells upregulate palladin during osteogenesis and in response to cyclic tensile strain. Am J Physiol Cell Physiol 293:C1532-8
Endlich, Nicole; Otey, Carol A; Kriz, Wilhelm et al. (2007) Movement of stress fibers away from focal adhesions identifies focal adhesions as sites of stress fiber assembly in stationary cells. Cell Motil Cytoskeleton 64:966-76
Ronty, Mikko J; Leivonen, Suvi-Katri; Hinz, Boris et al. (2006) Isoform-specific regulation of the actin-organizing protein palladin during TGF-beta1-induced myofibroblast differentiation. J Invest Dermatol 126:2387-96
Rachlin, Andrew S; Otey, Carol A (2006) Identification of palladin isoforms and characterization of an isoform-specific interaction between Lasp-1 and palladin. J Cell Sci 119:995-1004
Pogue-Geile, Kay L; Chen, Ru; Bronner, Mary P et al. (2006) Palladin mutation causes familial pancreatic cancer and suggests a new cancer mechanism. PLoS Med 3:e516
Goicoechea, Silvia; Arneman, Daniel; Disanza, Andrea et al. (2006) Palladin binds to Eps8 and enhances the formation of dorsal ruffles and podosomes in vascular smooth muscle cells. J Cell Sci 119:3316-24
Boukhelifa, Malika; Moza, Monica; Johansson, Thomas et al. (2006) The proline-rich protein palladin is a binding partner for profilin. FEBS J 273:26-33

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