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Protein kinase C-regulated dynamitin-macrophage-enriched myristoylated alanine-rice C kinase substrate interaction is

L Yue1, S Lu, J Garces

  • 1Department of Oral Biology, College of Dentistry, the Cancer Center and Department of Microbiology & Immunology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.

The Journal of Biological Chemistry
|May 29, 2000
PubMed

Insights

Dynamitin binds to MacMARCKS, a protein kinase C (PKC) substrate, influencing macrophage spreading. This interaction, regulated by PKC and calcium, is crucial for cell adhesion and spreading dynamics.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Macrophage spreading is essential for immune responses and relies on the microtubule cytoskeleton and protein kinase C (PKC).
  • The precise roles of microtubules and PKC in macrophage spreading remain unclear.
  • Dynamitin, a dynactin subunit, links dynein to membranes, but its function in cell spreading is not well-defined.

Purpose of the Study:

  • To investigate the interaction between dynamitin and MacMARCKS (macrophage-enriched myristoylated alanine-rice C kinase substrate).
  • To elucidate the role of the dynamitin-MacMARCKS interaction in macrophage cell spreading.
  • To explore the regulation of this interaction by PKC and Ca(2+)/calmodulin.

Main Methods:

  • Co-purification and co-sedimentation assays to confirm dynamitin-MacMARCKS interaction.
  • Identification of interacting domains using protein fragments.
  • Immunofluorescence microscopy to assess cellular localization.
  • Functional assays using peptides to disrupt the interaction.

Main Results:

  • Dynamitin binds directly to MacMARCKS, a PKC substrate involved in cell spreading.
  • The effector domain of MacMARCKS interacts with the N-terminal domain of dynamitin.
  • Dynamitin and MacMARCKS partially colocalize in macrophages and epithelial cells, with localization affected by phorbol ester treatment.
  • Disruption of the dynamitin-MacMARCKS interaction promotes macrophage spreading and flattening.

Conclusions:

  • The dynamitin-MacMARCKS interaction is a novel regulator of macrophage cell spreading.
  • Regulation of this interaction by PKC and Ca(2+)/calmodulin offers a mechanism for controlling cell adhesion and spreading.
  • This finding provides new insights into the molecular mechanisms governing cell motility and integrin activation.

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