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Updated: Aug 7, 2026
09:26
Identifying the Binding Proteins of Small Ligands with the Differential Radial Capillary Action of Ligand Assay (DRaCALA)
Published on: March 19, 2021
Streptococcus agalactiae CAMP factor binds to GPI-anchored proteins
Shenhui Lang1, Jie Xue, Zhongwu Guo
1Department of Chemistry, University of Waterloo, N2L 3G1 Waterloo, ON, Canada.
Medical Microbiology and Immunology
|June 15, 2006
Summary
Streptococcus agalactiae CAMP factor binds to GPI-anchored proteins, using their carbohydrate core. This interaction is crucial for CAMP factor
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- CAMP factor (protein B) is a pore-forming toxin secreted by Streptococcus agalactiae.
- It mediates lysis of sheep erythrocytes sensitized by staphylococcal sphingomyelinase.
- The precise mechanism of CAMP factor's cellular interaction remained unclear.
Purpose of the Study:
- To elucidate the molecular mechanism underlying CAMP factor's interaction with target cells.
- To identify the specific cellular components that serve as receptors for CAMP factor.
Main Methods:
- Investigated the binding of CAMP factor to various cell components.
- Utilized enzymatic cleavage of glycosylphosphatidylinositol (GPI) anchors using phosphatidylinositol-specific phospholipase C.
- Incorporated alkaline phosphatase, a model GPI-anchored protein, into liposome membranes.
Main Results:
- CAMP factor specifically binds to GPI-anchored proteins.
- The interaction involves the carbohydrate core of the GPI anchor.
- Enzymatic removal of GPI anchors significantly reduced erythrocyte sensitivity to CAMP factor.
- Liposomes containing alkaline phosphatase became susceptible to CAMP factor-induced permeabilization.
Conclusions:
- GPI-anchored proteins function as essential cellular receptors for CAMP factor.
- The carbohydrate moiety of the GPI anchor is critical for mediating this interaction.
- This finding provides a molecular basis for CAMP factor's cytolytic activity.
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