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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Hebbert, D. Articles by Morgan, E. H. Search for Related Content PubMed PubMed Citation Articles by Hebbert, D. Articles by Morgan, E. H. Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  Calmodulin antagonists inhibit and phorbol esters enhance transferrin endocytosis and iron uptake by immature erythroid cells D Hebbert and EH Morgan Seven antagonists of the calcium-binding protein calmodulin were found to inhibit iron and transferrin uptake by reticulocytes. This inhibition could be completely accounted for by inhibition of the endocytosis and exocytosis of transferrin. When four of the antagonists were tested with the nucleated erythroid cells from the liver of the fetal rat, inhibition of iron uptake was also observed but at higher concentrations than required for the same degree of inhibition with reticulocytes. The tumor promoters phorbol 12-myristate 13-acetate (PMA) and phorbol 12,13-dibutyrate (PDB) were shown to increase the rates of iron and transferrin uptake by reticulocytes and fetal liver erythroid cells by accelerating the rates of transferrin endocytosis and exocytosis. Since these substances are known to stimulate the calcium-activated enzyme protein kinase C while calmodulin antagonists are inhibitory, it is concluded that this enzyme plays an important role in the endocytosis and intracellular cycling of transferrin, and iron uptake by immature erythroid cells. However, the possibilities that calmodulin is also involved or that the inhibitory effects of the calmodulin antagonists are due to nonspecific actions on the cell membrane cannot be excluded. Volume 65, Issue 3, pp. 758-763, 03/01/1985 Copyright © 1985 by The American Society of Hematology CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: M. Lin, M. X. Zhu, and Y. Rikihisa Rapid Activation of Protein Tyrosine Kinase and Phospholipase C-{gamma}2 and Increase in Cytosolic Free Calcium Are Required by Ehrlichia chaffeensis for Internalization and Growth in THP-1 Cells Infect. Immun., February 1, 2002; 70(2): 889 - 898. [Abstract] [Full Text] [PDF]

	Copyright © 1985 by American Society of Hematology         Online ISSN: 1528-0020