The insect flight muscle Z disc is the most regularly ordered example of an actin cross-linking and anchoring assembly observed in nature. Its three dimensional structures will be determined by analysis of electron micrographs of tilted specimens using image processing techniques. The insect Z disc is a crystal with p3m projective symmetry. This symmetry will be exploited in the structure analysis to achieve a resolution of about 70 angstroms. Our preliminary studies of Z dics in projection at this resolution have resolved the actin filaments in the Z dics, and the connections between them. The proteins of the Z discs will be located in the structure by specific modification and labelling of Z discs, followed by structure analysis and comparison with the native Z disc. Actin filaments play a key role in the contractile apparatus of muscle cells. In non-muscle cells they have been implicated in cell migration and adhesion, cytokinesis, maintenance of cell shape, and endo- and exocytosis. in all of these systems the actin filaments must be anchored so contractile force can be transmitted through them. Recent bichemical and immunochemical characterization of a variety of such anchoring assemblies have uncovered strong structural homologies. As the most ordered example of this class of structures, the Z disc will be a valuable source of structural information of general applicability to actomyosin dependent cell motility.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR033141-03
Application #
3156519
Study Section
Biophysics and Biophysical Chemistry B Study Section (BBCB)
Project Start
1983-12-01
Project End
1988-08-31
Budget Start
1985-12-01
Budget End
1988-08-31
Support Year
3
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of Arizona
Department
Type
Schools of Arts and Sciences
DUNS #
City
Tucson
State
AZ
Country
United States
Zip Code
85722