The plasminogen receptor, Plg-R(KT), and macrophage function

Area of Science:

• Biochemistry
• Cell Biology
• Immunology

Background:

• Cell-surface plasminogen activation is significantly enhanced compared to solution-based reactions.
• Cell-surface plasmin is vital for macrophage recruitment in inflammatory processes.
• Proteins with exposed basic residues facilitate plasminogen activation on eukaryotic cells.

Purpose of the Study:

• To identify novel cell-surface proteins involved in plasminogen activation.
• To characterize the function and properties of a newly identified plasminogen receptor.

Main Methods:

• Proteomics approach utilizing targeted proteolysis with carboxypeptidase B.
• Multidimensional protein identification technology (MudPIT) applied to a monocyte progenitor cell line.
• Analysis of protein characteristics including membrane topology and sequence conservation.

Main Results:

• Identification of a novel transmembrane protein, plasminogen receptor (Plg-R(KT)).
• Plg-R(KT) exposes a C-terminal lysine, facilitating plasminogen binding and activation.
• Demonstrated role of Plg-R(KT) in plasminogen activation, cell migration, and macrophage recruitment.

Conclusions:

• Plg-R(KT) is a key mediator of cell-surface plasminogen activation.
• This receptor plays a significant role in inflammatory responses and cell motility.
• Understanding Plg-R(KT) offers insights into inflammatory mechanisms and potential therapeutic targets.