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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

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C1q and its growing family

Rohit Ghai1, Patrick Waters, Lubka T Roumenina

  • 1Institute of Medical Microbiology, Justus-Liebig-University, Frankfurter Strasse 107, 35392 Giessen, Germany.

Immunobiology
|June 5, 2007
PubMed

Insights

The globular C1q (gC1q) domain acts as a versatile scaffold, linking innate and acquired immunity by recognizing diverse ligands. Its structural similarity to TNF superfamily proteins highlights its broad functional importance.

Area of Science:

  • Immunology
  • Structural Biology
  • Biochemistry

Background:

  • C1q is the classical complement pathway's recognition protein, bridging innate and acquired immunity.
  • The globular domain (gC1q) of C1q recognizes various self and non-self ligands, initiating the classical pathway.
  • The gC1q domain is found in other proteins, forming the C1q family within the larger C1q and TNF superfamily.

Purpose of the Study:

  • To provide an updated review of the structural and functional characteristics of the human C1q gC1q domain.
  • To highlight the significance of the gC1q domain as a versatile structural scaffold.
  • To discuss the diverse functions supported by the gC1q domain across different proteins.

Main Methods:

  • Review of existing literature on C1q and related proteins.
  • Analysis of X-ray crystal structures of gC1q domains.
  • Comparative structural analysis with the TNF ligand family.

Main Results:

  • The gC1q domain adopts a jelly-roll beta-sandwich fold, similar to TNF superfamily members.
  • This domain's structure enables recognition of a wide array of ligands.
  • The gC1q domain serves as a conserved and adaptable scaffold for various biological functions.

Conclusions:

  • The gC1q domain is crucial for C1q's role in immunity and serves as a versatile structural motif in other proteins.
  • Understanding the gC1q domain's structure-function relationship is key to appreciating its broad biological relevance.
  • The C1q and TNF superfamily represents a significant group of proteins with diverse functions mediated by the gC1q domain.

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