CD97 is a processed, seven-transmembrane, heterodimeric receptor associated with inflammation

Area of Science:

• Cell biology
• Immunology
• Molecular biology

Background:

• CD97 is a G protein-coupled receptor primarily expressed in leukocytes.
• Its precise protein structure and function have remained largely undescribed.
• G protein-coupled receptors are characterized by seven transmembrane domains.

Purpose of the Study:

• To elucidate the protein structure and processing of the CD97 receptor.
• To investigate the functional implications of CD97's structure, particularly in the context of inflammation.

Main Methods:

• Analysis of CD97 protein processing in the endoplasmic reticulum and Golgi apparatus.
• Characterization of the cell surface expression of CD97 subunits.
• Investigation of CD97 expression in leukocytes at sites of inflammation.
• Detection of soluble CD97alpha in body fluids.

Main Results:

• CD97 undergoes intracellular processing into a two-subunit heterodimer (CD97alpha and CD97beta) before cell surface expression.
• CD97beta is evolutionarily related to the glucagon receptor family.
• CD97alpha exhibits alternatively spliced isoforms with epidermal growth factor-like repeats.
• CD97 expression is elevated in leukocytes at inflammatory sites, and soluble CD97alpha is found in inflamed tissues.

Conclusions:

• CD97 possesses a unique processing pathway among G protein-coupled receptors, forming a stable heterodimer.
• The presence of soluble CD97alpha in body fluids suggests a role in cell-free signaling.
• CD97 may function as a multifunctional protein involved in inflammatory processes and signal transduction.