Related Experiment Videos
Evidence against a laminin receptor role for calsequestrin
E S Choi1, P D Sullivan, D O Clegg
1Neuroscience Research Institute, University of California, Santa Barbara 93106.
Biochemical and Biophysical Research Communications
|February 14, 1991
Summary
Calsequestrin (CAL) is not a cell surface laminin receptor. Studies show CAL is not detected on live myotubes or adherent melanoma cells, challenging its proposed role in muscle cell adhesion.
Area of Science:
- Cell Biology
- Muscle Physiology
- Extracellular Matrix Interactions
Background:
- Calsequestrin (CAL), a muscle calcium-binding protein, was previously suggested to function as a cell surface laminin receptor.
- Initial evidence indicated CAL (aspartactin) localization on the cell surface, supporting a role in binding extracellular matrix protein laminin.
Purpose of the Study:
- To investigate and present evidence regarding the proposed laminin receptor function of calsequestrin (CAL).
- To determine the cellular localization of CAL and its effect on myotube adhesion and fusion.
Main Methods:
- Immunoreactivity detection of CAL on live and permeabilized cultured chick myotubes.
- Assessment of myotube adhesion and fusion rates on laminin in the presence of anti-CAL antibodies.
- Expression of CAL cDNA in a melanoma cell line to evaluate changes in laminin adhesion and CAL localization.
Main Results:
- CAL immunoreactivity was undetectable on live myotubes, requiring detergent permeabilization for detection.
- Anti-CAL antibodies did not affect myotube adhesion to or fusion on laminin.
- CAL expression in melanoma cells did not enhance laminin adhesion; CAL was primarily secreted, not cell surface-localized.
Conclusions:
- The findings do not support a role for calsequestrin (CAL) as a cell surface laminin receptor.
- CAL's cellular localization appears to be intracellular or secreted, rather than on the cell surface mediating adhesion.