R. Sanders Williams, MD

Other Professional Titles


(415) 734-2000


(415) 355-0820


Carolyn Provost
(415) 734-2064

Areas of Investigation

My research has focused on muscle plasticity: how cardiac and skeletal muscle cells sense and transduce signals from the environment to the genome, thereby altering their structural and metabolic capabilities to perform contractile work. For example, sustained exercise, such as long-distance running, alters mitochondrial biogenesis and specialized properties of the contractile apparatus, thereby increasing resistance to fatigue and reducing risk for diabetes and cardiovascular disease. We have sought to elucidate the molecular signaling pathways involved in these events, which are important to physiology and medicine.

Using cell culture assays and genetically modified mice, we identified a number of signaling proteins that participate in muscle plasticity. For example, we discovered how the protein phosphatase calcineurin and its downstream effector protein NFAT act synergistically with the transcription factor MEF2 at transcriptional enhancer elements of selected genes, such as myoglobin, to medicate adaptive mechanisms by which skeletal myofibers acquire specialized contractile and metabolic properties in response to changing patterns of muscle contraction. We also characterized the function of a family of endogenous inhibitors of calcineurin, originally termed MCIP but subsequently renamed as RCAN proteins. We identified and characterized a novel member of the forkhead gene family that is essential for proper regulation of satellite cells. These endogenous muscle stem cells promote regeneration of skeletal muscles after injury and that participate in adaptation to exercise.

These and other studies from the Williams lab contributed to current understanding of mitochondrial biogenesis, calcium-regulated signal transduction, tissue regeneration and muscle plasticity.


Co-founded the Center for Biomedical Invention, University of Texas Southwestern Medical Center, to translate discoveries in cell and molecular biology into useful medical therapeutics.
Defined basic principles of how skeletal and cardiac muscle cells adapt to changing physiological demands associated with exercise or disease states.
Discovered a novel transcription factor that modulates important steps in the transitions of adult myogenic stem cells to and from quiescence during muscle regeneration.
Characterized other proteins and pathways that modulate proliferation and differentiation of myogenic stem cells, hypertrophic growth of the heart, mitochondrial biogenesis and fiber type–specific gene expression in skeletal muscles.
Defined features of calcium-dependent gene regulation in myocyte plasticity.


  • Duke University
Alpha Omega Alpha
  • American Society of Clinical Investigation
  • Association of University Cardiologists
  • Association of American Physicians
  • National Academy of Sciences
  • Bristol-Myers Squib, Inc.
  • Laboratory Corporation of America
  • Board of Directors
  • Western Association of Physicians
  • SingHealth and Duke—NUS (Singapore)
  • Academic Medicine Advisory Council
  • Journal of Clinical Investigation
  • Editorial Board
  • American Journal of Physiology
  • Editorial Board
  • Circulation
  • Editorial Board
  • Circulation Research
  • Editorial Board
  • Science
  • Editorial Board
  • PLoS
  • Editorial Board

Professional titles


  • Princeton University
  • Duke University