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Inhibition of bFGF activity by complement C1s: covalent binding of C1s with bFGF

H Sakiyama1, K Kaji, K Nakagawa

  • 1Division of Cell Biology and Oncology, National Institute of Radiological Sciences, Chiba, Japan.

Cell Biochemistry and Function
|September 25, 1998
PubMed

Insights

The first complement component C1s forms aggregates with basic fibroblast growth factor (bFGF), reducing bFGF's growth-promoting activity. These aggregates, composed of C1s and bFGF, were dissociated by reducing agents.

Area of Science:

  • Biochemistry
  • Immunology
  • Cell Biology

Background:

  • Basic fibroblast growth factor (bFGF) is crucial for cell growth and tissue repair.
  • The first complement component (C1s) is a serine protease involved in the immune response.

Purpose of the Study:

  • To investigate the interaction between C1s and bFGF.
  • To determine the effect of this interaction on bFGF activity.

Main Methods:

  • Incubation of C1s and bFGF at 37°C overnight.
  • Analysis of aggregate formation using SDS-PAGE under reducing and non-reducing conditions.
  • Assessment of bFGF activity using human umbilical vein endothelial cells (HUVEC).

Main Results:

  • C1s formed large aggregates with bFGF, which were dissociable by 2-mercaptoethanol.
  • Both active and inactive C1s formed aggregates with bFGF.
  • Aggregate formation significantly reduced bFGF's growth-stimulating activity on HUVEC.
  • Active C1s partially degraded bFGF, while inactive C1s did not.

Conclusions:

  • C1s interacts with bFGF to form aggregates, thereby inhibiting bFGF's biological function.
  • This interaction has implications for understanding the regulation of growth factor activity by complement proteins.

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