Identification of high-affinity calmodulin-binding proteins in rat liver.

Published

Journal Article

The Ca2+-dependent binding of [125I]calmodulin (CaM) to hepatic proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was utilized to identify CaM binding or "acceptor" proteins or CAPs. Two proteins of apparent molecular weight of 60,000 (CAP-60) and 45,000 (CAP-45) comprised greater than 80% of the Ca2+-dependent CaM binding in rat liver cytosol. CAP-60 and CAP-45 were partially purified by a variety of chromatographic steps, including affinity chromatography on CaM Sepharose. CAP-60 possessed a native molecular size of 400,000, indicating it to be the CaM-binding "subunit" of a larger oligomeric complex. In contrast, CAP-45 was monomeric as judged by gel filtration. Neither CAP-60 nor CAP-45 possessed chromatographic properties consistent with known CaM-dependent enzymes reported in the literature. Two-dimensional peptide mapping provided convincing evidence that CAP-60 and CAP-45 were unrelated to other well-characterized CAPs, namely Ca2+ (CaM)-dependent protein kinase II, calcineurin, or the CaM-dependent cyclic nucleotide phosphodiesterase. The relative abundance and high affinity for CaM could suggest that these novel target proteins, CAP-60 and CAP-45, represent a dominant pathway for CaM action in the mammalian liver.

Full Text

Duke Authors

Cited Authors

  • Hanley, RM; Dedman, JR; Shenolikar, S

Published Date

  • March 1, 1987

Published In

Volume / Issue

  • 252 / 3 Pt 1

Start / End Page

  • C277 - C284

PubMed ID

  • 3469918

Pubmed Central ID

  • 3469918

International Standard Serial Number (ISSN)

  • 0002-9513

Digital Object Identifier (DOI)

  • 10.1152/ajpcell.1987.252.3.C277

Language

  • eng

Conference Location

  • United States