In my laboratory we are interested in understanding how the biophysical and biochemical properties of muscle proteins are coupled to muscle physiology. Most projects are designed to investigate fundamental principles of energy transduction by the protein-based machinery of skeletal muscle. In active muscle, tension development and shortening are coupled to the action of the actin-myosin motor system. I have been interested in the coupling force production to conformational changes in myosin for quite a while and one of the lab’s current points of focus is the potential for conformationally communicated cooperative interactions of myosin motors during force production. Another interest is the maintenance of skeletal muscle’s nearly crystalline geometry and its resistance of strain while relaxed. These properties are in part related to the function of the giant protein titin. We have been examining the role of site-directed modifications on titin structure and function. In general, our experiments are designed to reveal how changes in either protein structure or protein-protein interactions contribute the cellular physiology of muscle actions and responses.

The intricate organization and interaction of macromolecules in striated muscles provides a unique system for the study of the coupling of energy (chemical and mechanical) to physiological action (tension generation, active shortening, and response to strain). We use a combination of physiological measurements, site-directed protein modification and biophysical techniques to examine the mechanical and conformational dynamics of muscle proteins.

Muscle Physiology: Force development, the velocity of muscle shortening, passive strain and dynamic stiffness of muscle cells.

Muscle Biochemistry: Enzymatic activity, site-directed chemical modifications, electrophoresis, Western blotting.

Spectroscopy: UV/Vis Spectroscopy, Electron Paramagnetic Resonance Spectroscopy (EPR) and Confocal Microscopy are used to examine the activity, conformation and sarcomeric locations of cytoskeletal components.

By combining spectroscopic results with mechanical and biochemical data we can relate molecular level information to the physiological responses of skeletal muscle cells. The ultimate goal of our studies is to gain insights into the molecular mechanism of energy usage and force development in skeletal muscle.

Selected Publications

1. Barnett V.A. (2005) Cardiac Myocytes. In Handbook of Cardiac Anatomy, Physiology, and Devices, Paul A. Iaizzo editor. Humana Press pp. 113-121.

2. Barnett, V.A. (2001) Cross-bridge Cooperativity during Isometric Contraction and Unloaded Shortening of Skeletal Muscle. J. Mus. Res. Cell Motil. 22:415-423.

3. Xie, L., Li, W.X., Barnett, V.A. & Schoenberg, M. (1997). Graphical Evaluation of Alkylation of Myosin’s SH1 and SH2: The N-phenylmaleimide reaction. Biophys. J. 72:858-865.

4. Ehrlich, A., Barnett, V. A., Chen, H. & Schoenberg M. (1995). The Site and Stoichiometry of the N-Phenylmaleimide Reaction With Myosin When Weakly- binding Crossbridges are Formed in Skinned Rabbit Psoas Fibers. Biochem. Biophys. Acta 1232: 13-20.

5. Ostap, E. M., Barnett V. A. & Thomas, D. D. (1995). Resolution of Three Structural States of Spin-labeled Myosin in Contracting Muscle. Biophys. J. 69:177-188.

Dr. Vincent Barnett can be reached at: barne014@umn.edu