Earl E. Homsher, Ph.D.


Work Titles
UCLA Member, Molecular, Cellular & Integrative Physiology GPB Home Area Professor Emeritus, Physiology
Education:
Degrees:
Ph.D.

Contact Information:

Work Phone Number:

310-825-6424

310-825-6976

Work Address:

Laboratory
CHS
Los Angeles, CA 90095

Office
CHS
Los Angeles, CA 90095


Detailed Biography:

Research Interest: Regulation of crossbridge mechanisms We study the mechanism by which muscle or other molecular motors convert chemical energy (ATP) into mechanical work force, and shortening (chemomechanical transduction) and the calcium regulation of these processes. For this we use a variety of biochemical and biophysical techniques including: measurement of force, displacement, and stiffness in single muscle cells contracting under controlled conditions; measurement of the force exerted on single reconstituted fluorescently labled thin filaments (using microneedles) and their unloaded sliding speed in in vitro motility assays; measurement of force transients using single isolated myofibrils; and meaurements of force and displacement produced by single myosin molecules using optical trapping techniques. Reconstituted thin filaments are constructed from native and/or molecularly engineered actin, tropomyosin and/or troponin. We hope to learn the size of the crossbridge power stroke, the rates of specific crossbridge reaction steps, the identity of those steps affected by force exerted, displacement, [Ca+2], and the mechanisms of effects of regulatory protein mutations associated with Familial Hypertrophic Cardiomyopathy.

Publications:

A selected list of publications:

Piroddi, N Tesi, C Pellegrino, MA Tobacman, LS Homsher, E Poggesi, C   Contractile effects of the exchange of cardiac troponin for fast skeletal troponin in rabbit psoas single myofibrils The Journal of physiology. , 2003; 552(Pt 3): 917-31.
Heller, MJ Nili, M Homsher, E Tobacman, LS   Cardiomyopathic tropomyosin mutations that increase thin filament Ca2+ sensitivity and tropomyosin N-domain flexibility The Journal of biological chemistry. , 2003; 278(43): 41742-8.
Homsher, E Nili, M Chen, IY Tobacman, LS   Regulatory proteins alter nucleotide binding to acto-myosin of sliding filaments in motility assays Biophysical journal. , 2003; 85(2): 1046-52.
Morris, C.A., L.S. Tobacman, E. Homsher   Correlation of the level of thin filament activation with unloaded shortening velocity of rabbit skinned muscle fibers, J. Physiol. , 2003; 550: 205-215.
Burkart, E., M. P. Sumandea, T. Kobayashi, M. Nili, A. F. Martin, E. Homsher, and R.J. Solaro   Phosphorylation or Glutamic Acid Substitution at Protein Kinase C Sites on Cardiac Troponin I Differentially Depress Myofilament Tension and Shortening Velocity, J. Biol. Chem, 2003; 278: 11265-11272.
Sant'Ana Pereria, J., D. Pavlov, M. Greaser, E. Homsher, and R. Moss   Kinetic differences in cardiac myosins with identical loop1 sequences, J. Biol. Chem, 2001; 276: 4409-4415.
Morris, C., L.S. Tobacman, and E. Homsher   Modulation of contractile activation in skeletal muscle by CBMII, a Ca2+-insensitive troponin C mutant, J. Biol. Chem, 2001; 276: 20245-20251.
Gordon, A., E. Homsher, and M. Regnier   Regulation of Contraction, Physiol. Rev, 2000; 80: 853-924.
Homsher, E Lee, DM Morris, C Pavlov, D Tobacman, LS   Regulation of force and unloaded sliding speed in single thin filaments: effects of regulatory proteins and calcium The Journal of physiology. , 2000; 524 Pt 1: 233-43.
Tobacman, LS Lin, D Butters, C Landis, C Back, N Pavlov, D Homsher, E   Functional consequences of troponin T mutations found in hypertrophic cardiomyopathy The Journal of biological chemistry. , 1999; 274(40): 28363-70.

Does this profile need updating? Contact Us