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Coated vesicles from developing and adult rat skeletal muscles contain multiple molecular forms of acetylcholinesterase
Author(s) -
HodgesSavola C. A.,
Gregory E. J.,
Rummel S. A.,
Fernandez H. L.
Publication year - 1989
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490240208
Subject(s) - acetylcholinesterase , aché , biochemistry , clathrin , gene isoform , vesicle , cell fractionation , skeletal muscle , biology , immunoadsorption , chemistry , microbiology and biotechnology , enzyme , anatomy , membrane , immunology , gene , antibody
The main purpose of this work was to determine which of the multiple isoforms of acetylcholinesterase (AChE) are associated with clathrin‐coated vesicles (CVs) from developing and adult rat skeletal muscles. CV‐enriched preparations were obtained by subcellular fractionation/equilibrium sedimentation and further purified by immunoadsorption to anti‐clathrin IgG‐coated Staphylococcus aureus cells. Analysis of individual AChE isoforms by velocity sedimentation ultracentrifugation showed that (a) while both globular (G‐forms) and asymmetric (A‐forms) AChE were detected in all subcellular fractions evaluated, the CV‐enriched fraction contained a higher proportion of A‐forms (mainly the A 12 species); (b) most of the AChE activity contained in such a CV fraction was recovered following immunoadsorption; (c) alkaline extraction conditions (pH 8.5) which depolymerize clathrin were necessary to detect a large proportion of A‐forms in both the CV‐enriched and immunoprecipitated preparations, while most of the G‐forms (especially G 1 + G 2 AChE) were detected following extraction at pH 6.8; and (d) comparison of AChE isoform profiles from neonate and adult muscle CV‐enriched fractions showed a greater concentration of A‐forms in the former. These data suggest that considerable amounts of A 12 and, to a lesser extent, G 4 AChE are sequestered within muscle CVs which may be destined for the plasmalemma. Our findings also indicate that the relative proportions of AChE isoenzymes in rat muscle CVs vary according to the extent of muscle development and lend support to the contention that CVs participate in the externalization of functionally important AChE isoenzymes.