Penn Medicine

Clara Franzini-Armstrong, Ph.D.

Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine

Contact Information

Department of Cell and Developmental Biology
Philadelphia, PA 19104-6058
Phone: (215) 898-8568
Fax: (215) 898-9871
Position: Professor


My laboratory uses high resolution shadowing techniques to study the shape and disposition of macromolecules in striated muscle cells. The imaging of the calcium adenosine triphophatase (ATPase) (calcium pump) protein on the surface of intact and isolated sarcoplasmic reticulum has led to a better understanding of the density and state of aggregation of the molecule in its native state.

Myosin cross bridges are being studied in vertebrate and arthropod muscles in rigor, to establish whether both myosin heads participate in the formation of cross bridges under steric conditions imposed by the complex arrangement of the sarcomere.

Representative Publications

  1. Hirose, K., Franzini-Armstrong, C., Goldman, Y., and Murray, J.M. 1994 Structural changes in muscle cross-bridges accompanying force generation. J. Cell Biol. 127:763-778.
  2. Sun, X-H., Protasi, F., Takahashi, M., Takeshima, H., Ferguson, D.G. and Franzini-Armstrong, C. 1995. Molecular architecture of membranes involved in excitation-contraction coupling of cardiac muscle. J. Cell Biology. 129:659-673.
  3. Takekura, H., Nishi, M., Noda, T., Takeshima, H., and Franzini-Armstrong, C. 1995. Abnormal junctions between surface membrane and sarcoplasmic reticulum in skeletal muscle with a mutation targeted for the ryanodine receptor. Procs. Natl. Acad. Sci. USA. 92:3381-3385.
  4. Franzini-Armstrong, C. and Kish, C.W. 1995. Alternate disposition of tetrads in peripheral couplings of skeletal muscle. J. Muscle Res. Cell Motil. 16:319-324.
  5. Takekura, H., Takeshima, H., Nishimura, S., Imoto, K., Takahashi, M., Tanabe, T., Flockerzi, V., Hofman, F. and Franzini-Armstrong, C. 1995. Co-expression in CHO cells of two muscle proteins involved in excitation contraction coupling. J. Muscle Res. Cell Motil. 16:465-480.
  6. Protasi, F., Sun, X-H. and Franzini-Armstrong, C. 1996. Formation and maturation of calcium release units in developing and adult avian myocardium. Dev. Biol. 173:265-278.
  7. Lenart, T.L., Murray, J.M., Franzini-Armstrong, C. and Goldman, Y.E. 1996. Structure and periodicities of cross-bridges in relaxation, rigor and during contractions initiated by photolysis of caged Ca2+. Biophys. J. 71:2289-2306.
  8. E. Varriano-Marston, Franzini-Armstrong and J. Haselgrove. The structure and disposition of cross-bridges in deep-etched fish muscle. J. Muscle Research Cell Motility 5:363-386, 1984.
  9. C. Franzini-Armstrong and D.G. Ferguson. Density and disposition of CaATPase in sacroplasmic reticulum membrane as determined by shadowing techniques. Biophys. J. 48:607-615, 1985.
  10. B.A. Block and C. Franzini-Armstrong. The structure of the membrane system in a novel muscle cell modified for heat production. J. Cell Biology 107:1099-1112, 1988.
  11. K.E. Loesser and C. Franzini-Armstrong. A simple method for freeze-drying of macromolecules and macromolecular complexes. J. Structural Biology 103:48-56, 1990.
  12. B.A. Block, T. Imagawa, K.P. Campbell and C. Franzini-Armstrong. Structural evidence for direct interaction between the molecular components of the transverse tubules/sarcoplasmic reticulum junction in skeletal muscle. J. Cell Biol. 107:2587-2600, 1988.


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