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Ultrastructural localization of calcium binding sites on human muscle cell surface
Author(s) -
Moggio M.,
Jann S.,
Adobbati L.,
Prelle A.,
Gallanti A.,
Fagiolari G.,
Pellegrini G.,
Scarlato G.
Publication year - 1989
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880121107
Subject(s) - sarcolemma , basal lamina , sialic acid , calcium , biophysics , chemistry , ultrastructure , cell membrane , microbiology and biotechnology , biochemistry , biology , cell , membrane , anatomy , organic chemistry
Calcium (Ca 2+ ) is mainly bound to anionic phospholipids and to sialic acid at the cell surface. We studied the ultrastructural localization of these Ca 2+ binding sites in normal human muscle fibers, using Polymyxin B as a marker for anionic phospholipids and the lectin Limulus Polyphemus as a probe for sialic acid. We found that anionic phospholipids have a patchy distribution along the muscle sarcolemma, with a preferential localization at the I band level and at the junction between the I and A band. Sialic acid has an uniform distribution along the muscle plasma membrane and basal lamina. Our observations suggest that the plasma membrane, basal lamina, and transverse tubular system play an important role in providing the negative charge of the human muscle cell surface and that these structures may be involved in the binding of calcium.