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Acta Physiologica 2009; Volume 195, Supplement 669
The 88th Annual Meeting of The German Physiological Society
3/22/2009-3/25/2009
Giessen, Germany
LASP-2 EXPRESSION, LOCALIZATION, AND LIGAND INTERACTIONS:A NEW Z-DISC SCAFFOLDING PROTEIN
Abstract number: O524
Zieseniss1 A., Terasaki2 A., Mentrup3 V., Gregorio3 C. C.
1Department of Cardiovascular Physiology, Institute for Physiology and Pathophysiology, Gttingen
2Chiba University, Graduate School of Science and Technology, Chiba, Japan
3University of Arizona, Department of Cell Biology and Anatomy, Tucson, United States of America
The nebulin family of actin-binding proteins plays an important role in actin filament dynamics in a variety of cells including striated muscle. We report here the identification of a new striated muscle Z-disc associated protein: lasp-2 (LIM and SH3 domain protein-2). Lasp-2 is the most recently identified member of the nebulin family and was found widely expressed in different tissues including brain, kidney, lung placenta and pancreas.
To evaluate a possible role of lasp-2 in striated muscle, lasp-2 gene expression and localization were studied in chick and mouse tissue, as well as in primary cultures of chick cardiac and skeletal myocytes. Lasp-2 mRNA was detected as early as chick embryonic stage 25 and lasp-2 protein was associated with developing premyofibril structures, Z-discs of mature myofibrils, and intercalated discs of cultured cardiomyocytes. Expression of GFP-tagged lasp-2 deletion constructs showed that the C-terminal region of lasp-2 is important for its localization in striated muscle cells. Lasp-2 organizes actin filaments into bundles and interacts directly with the Z-disc protein alpha-actinin. These results are consistent with a function of lasp-2 as a scaffolding and actin filament organizing protein within striated muscle Z-discs. Presently we are seeking to identify putative binding partners and are analysing the effects of siRNA mediated lasp-2 knock-down in primary myocytes and C2C12 myoblasts. Interestingly our initial results show that spreading of C2C12 myoblasts is delayed in cells with reduced lasp-2 protein levels.
To cite this abstract, please use the following information:
Acta Physiologica 2009; Volume 195, Supplement 669 :O524