Blog
About

  • Record: found
  • Abstract: found
  • Article: not found

Evidence for a dithiol-activated signaling pathway in natural killer cell avidity regulation of leukocyte function antigen-1: structural requirements and relationship to phorbol ester- and CD16-triggered pathways.

Blood

Naphthalenes, metabolism, Animals, Cations, Divalent, Cell Adhesion, drug effects, Cytoskeleton, physiology, Dithiothreitol, pharmacology, Ethers, Cyclic, Gene Expression Regulation, Humans, Intercellular Adhesion Molecule-1, biosynthesis, genetics, Killer Cells, Natural, Lymphocyte Function-Associated Antigen-1, Membrane Proteins, Mice, Actins, Neoplasm Proteins, Okadaic Acid, Oxazoles, Oxidation-Reduction, Phosphoprotein Phosphatases, antagonists & inhibitors, Phosphorylation, Protein Conformation, Protein Kinase C, Protein Processing, Post-Translational, Protein-Tyrosine Kinases, Receptors, IgG, Signal Transduction, Structure-Activity Relationship, Sulfhydryl Reagents, chemistry, Tetradecanoylphorbol Acetate, Tumor Cells, Cultured

Read this article at

ScienceOpenPubMed
Bookmark
      There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

      Abstract

      Dithiothreitol (DTT) activation of the adhesive function of several different integrins suggests the existence of a common DTT-sensitive integrin regulatory element. Ui11/E3, a natural killer (NK) cell-resistant murine target cell line genetically engineered to constitutively express human intercellular adhesion molecule-1 (ICAM-1; CD54) was used in a flow cytometric experimental model to evaluate DTT effects on the NK cell integrin adhesion molecule, leukocyte function antigen-1 (LFA-1; alpha L beta 2, CD11a/CD18). DTT and several structurally related dithiol compounds elicited a dramatic elevation in conjugate formation that was dependent on target cell ICAM-1 expression, was blocked by LFA-1 alpha L or beta 2 chain-specific antibodies, and occurred in the absence of Ui11/E3 target cell exposure to DTT or quantitative changes in NK cell membrane LFA-1 expression. This avidity modulation of LFA-1 by DTT required actin polymerization, was abrogated by the protein kinase C inhibitor calphostin C, involved activities of calyculin A- and okadaic acid-sensitive serine/threonine protein phosphatases PP-1 and/or PP-2A but not geldanamycin-sensitive tyrosine kinases, and differed with respect to kinetics and enzyme inhibitor sensitivity from LFA-1 activation promoted by cross-linking of NK cell CD16 or phorbol ester treatment. A key structural feature of DTT was the presence of two thiol groups, both reduced but not physically adjacent as in the nonstimulatory dithiol, 2,3-dimercaptopropanol. LFA-1 activation was not because of DTT chelation of Ca2+ or Zn2+. Immunoblotting studies identified multiple NK cell plasma membrane-associated proteins to be reduced by DTT under LFA-1-activating conditions, but similar effects were also promoted by reducing agent treatments that failed to alter adhesive function. Direct chemical modification of LFA-1 seemed an unlikely basis of activation because (1) DTT activated LFA-1 in HSB2 T cells without detectable disulfide reduction in LFA-1 alpha L or beta 2 chains immunoprecipitated from these cells and (2) DTT treatment of NK cells did not hinder binding of KIM127 and KIM185, monoclonal antibodies that recognize epitopes in the potentially DTT-susceptible cysteine-rich domain of the beta 2 chain. Thus, these results extended the range of DTT-activatible integrins to include NK cell LFA-1 and characterized for the first time signaling-associated enzymatic activities involved in DTT activation of NK cell LFA-1. Moreover, they suggested that structural features of DTT, particularly SH group spatial positioning, are important in LFA-activation for reasons other than cation chelation or disulfide reduction.(ABSTRACT TRUNCATED AT 400 WORDS)

      Related collections

      Author and article information

      Journal
      7662976

      Comments

      Comment on this article