Surface functions during mitosis in rat basophilic leukemia cells.

Area of Science:

• Cell Biology
• Immunology
• Molecular Biology

Background:

• Cells lose membrane activities like phagocytosis upon entering mitosis.
• Mitotic cells exhibit resistance to functional responses triggered by cell surface ligand-receptor interactions.

Purpose of the Study:

• To investigate whether mitotic cells resist functional responses to cell surface ligand-receptor interactions.
• To determine the impact of mitosis on IgE receptor-mediated signaling and cell surface dynamics.

Main Methods:

• Utilized RBL-2H3 rat basophilic leukemia cells labeled with anti-dinitrophenol IgE (anti-DNP-IgE).
• Cross-linked IgE receptors with multivalent ligands (DNP-bovine serum albumin [BSA], DNP-B-phycoerythrin, DNP-BSA-gold).
• Assessed [3H]serotonin release, cell surface topography changes, and fluid pinocytosis in interphase versus mitotic cells.

Main Results:

• IgE-receptor complexes remained on the cell surface throughout mitosis, binding ligands and redistributing to coated pits.
• Antigen stimulation failed to induce significant [3H]serotonin release in mitotic cells.
• Mitotic cells maintained a microvillous surface and ceased fluid pinocytosis, unlike interphase cells.

Conclusions:

• Mitosis-specific impairment of membrane and secretory responses is likely caused by a failure in transmembrane signaling.
• Cell surface receptor-ligand interactions are functionally suppressed during mitosis.
• Protein kinase C activation can restore some membrane activities in mitotic cells.