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Evaluation of the Interplay Between the Complement Protein C1q and Hyaluronic Acid in Promoting Cell Adhesion
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Published on: June 15, 2019

Adiponectin binds C1q and activates the classical pathway of complement

Philip W Peake1, Yvonne Shen, Alexandra Walther

  • 1Division of Medicine, Prince of Wales Hospital, High Street, Randwick, Sydney, NSW 2031, Australia.

Biochemical and Biophysical Research Communications
|January 9, 2008
PubMed

Insights

Adiponectin binds to C1q, activating the complement system. This suggests adiponectin

Area of Science:

  • Immunology
  • Biochemistry

Background:

  • Adiponectin, an adipose-specific protein, binds to various targets like damaged endothelium and apoptotic cells.
  • The functional significance of adiponectin binding remains largely undetermined.

Purpose of the Study:

  • To investigate the interaction between adiponectin and C1q.
  • To elucidate the role of adiponectin in innate immunity and complement activation.

Main Methods:

  • Purified C1q binding assays with recombinant and serum-derived adiponectin.
  • Complement activation studies involving C4 and C3 deposition.
  • Western blotting and periodate treatment to assess binding characteristics.

Main Results:

  • Purified C1q binds to adiponectin under physiological conditions, dependent on Ca(++) and Mg(++).
  • Binding is enhanced by modification of adiponectin's sugars and involves the globular domain of C1q.
  • C1q binding to adiponectin triggers classical complement pathway activation, leading to C4 and C3 deposition.

Conclusions:

  • Adiponectin interacts with C1q, a key component of the complement system.
  • Adiponectin may function as a pattern-recognition molecule within the innate immune system.
  • This interaction suggests a novel role for adiponectin in immune responses and autoimmune conditions.

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