The third component of complement: new functions for an old friend

Area of Science:

• Immunology and Biochemistry

Background:

• The complement system protein C3 is a key mediator in various biological processes.
• Its unique thiolester-containing biochemistry and high physiological concentrations suggest underappreciated functions.
• C3 is abundant in plasma and widely distributed in tissues.

Purpose of the Study:

• To review and highlight four biological processes where C3 acts as a primary mediator.
• To emphasize the need for further investigation into these novel C3 functions.
• To underscore the potential of C3's biochemical properties and physiological distribution in understanding its roles.

Main Methods:

• Literature review of existing studies on C3 functions.
• Analysis of C3 biochemistry, focusing on its thiolester group.
• Examination of C3's concentration and distribution in plasma and tissues.

Main Results:

• Identification of four biological processes requiring further C3 investigation.
• Elucidation of how C3's thiolester biochemistry contributes to its functions.
• Recognition of C3's high plasma concentration and tissue presence as indicators of its importance.

Conclusions:

• C3 possesses versatile and potentially underappreciated functions in various biological processes.
• Further research, aided by genetic manipulation techniques, is crucial to fully understand C3's pluripotent nature.
• The biochemistry and physiological characteristics of C3 warrant extensive investigation.