Thrombin-stimulated cell division involves proteolysis of its cell surface receptor

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Biology

Background:

• Thrombin is known to have mitogenic effects on various cell types.
• The precise mechanism by which thrombin stimulates cell division is not fully understood.

Purpose of the Study:

• To investigate the role of cell-surface interactions in thrombin-induced cell proliferation.
• To identify the specific cell-surface component that mediates thrombin's mitogenic action.

Main Methods:

• Utilizing a photoreactive derivative of thrombin to identify its cell-surface receptor.
• Analyzing the cleavage of cell-surface components in response to thrombin treatment in dividing versus non-dividing cells.

Main Results:

• A cell-surface component with a molecular weight of 43,000 is specifically cleaved by thrombin on cells that subsequently divide.
• Cells unresponsive to thrombin's mitogenic effects do not exhibit cleavage of this 43,000 molecular weight component.
• Photoreactive thrombin studies confirmed that the cell-surface receptor has a molecular weight of 43,000.

Conclusions:

• Thrombin must cleave its 43,000 molecular weight cell-surface receptor to initiate the signaling pathway for cell division.
• The cleavage of this receptor is a critical step in thrombin's mitogenic action.