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Updated: Jun 4, 2025

Evaluation of the Interplay Between the Complement Protein C1q and Hyaluronic Acid in Promoting Cell Adhesion
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Evaluation of the Interplay Between the Complement Protein C1q and Hyaluronic Acid in Promoting Cell Adhesion

Published on: June 15, 2019

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Characterization of the binding of the globular domains of the complement component C1q to phosphatidylserine

Alexandra Kapogianni1, Gabriela Radulova1, Vancho Donev2

  • 1Sofia University "St. Kliment Ohridski", Faculty of Biology, Department of Biochemistry, Bulgaria.

International Journal of Biological Macromolecules
|December 26, 2024
PubMed

Insights

Complement C1q binds externalized phosphatidylserine on apoptotic cells. This study identifies the phosphatidylserine-binding site on C1q

Area of Science:

  • Immunology
  • Molecular Biology
  • Structural Biology

Background:

  • C1q initiates the classical complement pathway.
  • C1q clears apoptotic cells by binding externalized phosphatidylserine.
  • Understanding C1q-phosphatidylserine interaction is crucial for immune response.

Purpose of the Study:

  • Characterize the C1q-phosphatidylserine interaction.
  • Elucidate the structure of the phosphatidylserine-binding site in C1q globular domains.
  • Identify key amino acids involved in binding.

Main Methods:

  • In vitro binding assays.
  • In silico structural analysis.
  • Biochemical characterization of C1q fragments.

Main Results:

  • All three globular fragments of C1q bind phosphatidylserine.
  • The A chain of the C1q globular fragment plays a leading role in binding.
  • Specific amino acids, including glycosylated Asn124, were identified at the binding site.

Conclusions:

  • The A chain harbors the primary phosphatidylserine-binding site.
  • Glycosylated Asn124 is important for C1q-phosphatidylserine interaction.
  • Detailed structural insights into C1q-mediated efferocytosis.

Keywords:
ApoptosisComplement C1qGlobular domainsMolecular dynamics modellingPhosphatidylserineProtein-lipid interaction

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