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Specific changes in the posttranslational regulation of nucleolin in lymphocytes from patients infected with human

Domenico Galati1, Mirko Paiardini, Barbara Cervasi

  • 1Dipartimento di Internistica Clinica e Sperimentale "F. Magrassi," Seconda Universita' degli Studi di Napoli, Napoli, Italy.

The Journal of Infectious Diseases
|November 19, 2003
PubMed

Insights

Human immunodeficiency virus (HIV) infection disrupts lymphocyte cell cycles, altering nucleolin protein. This study links abnormal cyclin B1/p34 cdc2 activation to nucleolin changes and increased lymphocyte apoptosis in HIV patients.

Area of Science:

  • Immunology
  • Molecular Biology
  • Virology

Background:

  • Lymphocytes from human immunodeficiency virus (HIV)-infected patients exhibit cell-cycle dysregulation.
  • This includes aberrant activation of the cyclin B1/p34 cdc2 complex and abnormal nucleolar structure.

Purpose of the Study:

  • To investigate the posttranslational regulation of nucleolin, a critical nucleolar structural protein.
  • To elucidate the molecular mechanisms underlying HIV-associated cell-cycle perturbations.

Main Methods:

  • Analysis of nucleolin's posttranslational modifications in concanavalin A-stimulated lymphocytes from HIV-infected patients.
  • Assessment of cyclin B1/p34 cdc2 kinase activity, nucleolin phosphorylation, fragmentation, and localization.
  • Correlation of nucleolin localization with lymphocyte apoptosis.

Main Results:

  • In HIV-infected lymphocytes, inappropriate cyclin B1/p34 cdc2 activation correlates with increased nucleolin threonine phosphorylation and fragmentation.
  • Abnormal extranuclear and cell-surface localization of nucleolin was observed.
  • Increased lymphocyte apoptosis coincided with nucleolin cell-surface localization.

Conclusions:

  • These findings suggest a direct molecular link between dysregulated cyclin B1/p34 cdc2 activity and altered nucleolar structure in HIV infection.
  • The study provides a more precise molecular definition of cell-cycle dysregulation in HIV.
  • Nucleolin's aberrant localization may play a role in HIV-associated lymphocyte apoptosis.

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