Biography

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   We study physiological processes that modify and regulate the plasma membrane of cells. Initially we   studied the function and regulation of Na transporters that regulate cardiac myocyte function and determine cardiac fate in metabolic stress.  We developed new electrical methods to do so, and we achieved microsecond resolution of partial reactions of transporters.  We went on to study how lipids regulate ion channels and transporters, and we discovered that the negatively charged lipid, PIP2, directly regulates and is essential for activity of many transport processes.  We refined electrical methods to monitor electroneutral ion fluxes in cells and isolated membrane patches.  We are now concentrated on turnover of the surface membrane. We have identified new mechanisms that can remove surface membrane more rapidly and more extensively than conventional endocytosis, which relies on membrane adapter proteins, such as clathrin and dynamin. These non-conventional mechanisms rely on domain formation within membranes. They can be active constitutively, and the become highly activated in metabolic stress. They are involved in multiple cell processes that require membrane turnover, including cell migration and particle uptake.  In addition, we discovered a new mechanism of plasma membrane expansion that does not appear to involve exocytosis. In many cells, large fractions of the surface membrane are locked into closed invaginations that are not ‘excised’ from the surface. This large membrane reserve can be opened when needed to expand the surface during cell swelling or spreading, as well as other processes that require more membrane area. In summary, I have strived throughout my career to bring new approaches and difficult experimentation to bear on outstanding open questions related to membrane biology and ion transport. In recognition for these contributions, I was elected to the National Academy of Sciences in 2021.

Education

Graduate School
University of Tuebingen , Biology
Medical School
University of Tuebingen (1980), Medicine

Research Interest

  • Calcium Signaling
  • Electrophysiology
  • Lipid Signaling
  • Membrane transport mechanisms
  • Nonconventional endocytic mechanisms

Publications

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Honors & Awards

  • National Academy of Science
    Election to the Physiology/Pharmacology Section of the NAS (2121)
  • 1983
    Lievre Research Award for best cardiovascular research, Greater Los Angeles (0)
  • 1989-1992
    Established Investigatorship, American Heart Association (0)
  • 1993
    Fellow, Japan Society for the Promotion of Science (University of Kyoto) (0)
  • 1997
    Young Investigator Award: International Biophysical Society (0)

Professional Associations/Affiliations

  • Biophysical Society