Characterization of Ca(2+)-ATPase in rod outer segment disk membranes

The Ca(2+)-pump isolated in rod outer segment disk membranes as aspartylphosphate intermediate E-P has been characterized: the 100 kDa phosphoprotein was completely inhibited by thapsigargin, was not sensitive to digestion by calpain, and displayed a tryptic digestion pattern with the formation of t...

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Bibliographic Details
Published inBiochemical and biophysical research communications Vol. 204; no. 2; pp. 813 - 819
Main Authors Panfoli, I, Morelli, A, Pepe, I M
Format Journal Article
LanguageEnglish
Published United States 28.10.1994
Subjects
Animals
Calcium-Transporting ATPases - antagonists & inhibitors
Calcium-Transporting ATPases - metabolism
Cattle
Cell Membrane - drug effects
Cell Membrane - metabolism
Hydrolysis
Rod Cell Outer Segment - enzymology
Terpenes - pharmacology
Thapsigargin
Trypsin - metabolism
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Summary:The Ca(2+)-pump isolated in rod outer segment disk membranes as aspartylphosphate intermediate E-P has been characterized: the 100 kDa phosphoprotein was completely inhibited by thapsigargin, was not sensitive to digestion by calpain, and displayed a tryptic digestion pattern with the formation of two autophosphorylatable fragments of about 55 and 35 kDa. These results are typical of the calcium pumps of sarcoplasmic or endoplasmic reticulum calcium and differ from those of plasma membrane, such as the Ca(2+)-ATPase of the red blood cells, here shown as controls. The physiological role of calcium pump in disk membranes of vertebrate photoreceptors is discussed in terms of intracellular calcium buffering.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
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ISSN:0006-291X
DOI:10.1006/bbrc.1994.2532