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The activation of CD99 inhibits cell-extracellular matrix adhesion by suppressing β(1) integrin affinity

Kyoung-Jin Lee1, Sun-Hee Lee, Birendra Kumar Yadav

  • 1Departments of Anatomy and Cell Biology, School of Medicine, College of Natural Sciences, Kangwon National University, Chunchon, Korea.

BMB Reports
|March 28, 2012
PubMed

Insights

CD99 activation inhibits cell-extracellular matrix adhesion by suppressing beta(1) integrin affinity. This study reveals CD99

Area of Science:

  • Cell biology
  • Molecular biology
  • Biochemistry

Background:

  • CD99 protein regulates cell-cell adhesion.
  • Its role in cell-extracellular matrix (ECM) adhesion is not well understood.

Purpose of the Study:

  • Investigate the impact of CD99 activation on cell-ECM adhesion.
  • Elucidate the underlying molecular mechanisms.

Main Methods:

  • Utilized MCF-7 cells and stimulating antibody YG32 to activate CD99.
  • Employed dominant-negative CD99 overexpression and CD99 siRNA for inhibition studies.
  • Assessed cell adhesion to fibronectin, laminin, and collagen IV.
  • Analyzed beta(1) integrin activity and FAK phosphorylation.

Main Results:

  • CD99 activation dose-dependently downregulated MCF-7 cell adhesion to ECM proteins.
  • Inhibition of CD99 signaling blocked this downregulation effect.
  • Treatment with Mn(2+) or a beta(1) integrin-stimulating antibody restored CD99's inhibitory effect.
  • CD99 cross-linking inactivated beta(1) integrin via conformational changes.
  • CD99 activation led to dephosphorylation of FAK at Tyr-397.

Conclusions:

  • CD99 activation inhibits cell-ECM adhesion.
  • This inhibition occurs through the suppression of beta(1) integrin affinity.
  • CD99 signaling impacts focal adhesion kinase (FAK) activity.

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