Penn Medicine

Annemarie Weber, MD

Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine

Contact Information

Department of Biochemistry and Biophysics
School of Medicine
Philadelphia, PA 19104-6059
Phone: (215) 898-6392
Position: Professor


Dr. Weber studies the mechanism of action by which actin binding proteins regulate the assembly and disassembly of actin filaments. At the moment the laboratory is focusing on proteins that may be involved in length regulation of actin filaments in muscle and non-muscle cells. Two such proteins are tropomyosin, which polymerizes along the length of actin filaments and tropomodulin, a protein that caps the slowly reacting end of the actin filament in a complex manner. At the moment the lab is working on three projects which attempt to answer the following questions:

  • Does the mechanism by which the energy of ATP hydrolysis is used in the action of tropomodulin, the pointed end capping protein, involve a change in the nucleotide content of the terminal actin molecules?
  • Where on tropomodulin is the binding site for actin?
  • Does the cooperation between tropomodulin and tropomyosin require that the two proteins are bound to each other?

Representative Publications

  1. Gregorio CC. Weber A. Bondad M. Pennise CR. Fowler VM. Requirement of pointed-end capping by tropomodulin to maintain actin filament length in embryonic chick cardiac myocytes. Nature. 377(6544):83-86. 1995. [Abstract]
  2. Weber A. Pennise CR. Pring M. DNase I increases the rate constant of depolymerization at the pointed (-) end of actin filaments. Biochem. 33:4780-4786. 1994. [Abstract]
  3. Weber A. Pennise CR. Babcock GG. Fowler VM. Tropomodulin caps the pointed ends of actin filaments. J. Cell Biol. 127:1627-1635. 1994. [Abstract]
  4. Weber A. Nachmias VT. Pennise CR. Pring M. Safer D. Interaction of thymosin beta 4 with muscle and platelet actin: implications for actin sequestration in resting platelets. Biochem. 31:6179-6185. 1992. [Abstract]
  5. Weber A. Pring M. Lin SL. Bryan J. Role of the N- and C-terminal actin-binding domains of gelsolin in barbed filament end capping. Biochem. 30:9327-34. 1991. [Abstract]
  6. Young CL. Southwick FS. Weber A. Kinetics of the interaction of a 41-kilodalton macrophage capping protein with actin: promotion of nucleation during prolongation of the lag period. Biochem. 29:2232-2240. 1990. [Abstract]
  7. Broschat KO. Weber A. Burgess DR. Tropomyosin stabilizes the pointed end of actin filaments by slowing depolymerization. Biochem. 28:8501-8506. 1989. [Abstract]
  8. Northrop J. Weber A. Mooseker MS. Franzini-Armstrong C. Bishop MF. Dubyak GR. Tucker M. Walsh TP. Different calcium dependence of the capping and cutting activities of villin. J. Biol. Chem. 261:9274-9281. 1986. [Abstract]


Pennsylvania Muscle Institute
Perelman School of Medicine University of Pennsylvania
Director: E. Michael Ostap, Ph.D.

700A Clinical Research Building Philadelphia, PA 19104-6085 Phone: (215) 573-9758 Fax: (215) 898-2653