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A PI(4,5)P2-derived "gasoline engine model" for the sustained B cell receptor activation
Chenguang Xu1, Zhengpeng Wan1, Samina Shaheen1
1Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China.
Immunological Reviews
|August 13, 2019
Summary
Lymphocytes use a signaling amplification mechanism involving phosphatidylinositol (PI) 4,5-biphosphate (PI(4,5)P2) synthesis and hydrolysis for sustained B cell activation. This process, likened to a gasoline engine, ensures efficient immune responses.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Lymphocytes require efficient signaling amplification to respond to rare microenvironmental ligands.
- A recently reported mechanism involves phosphatidylinositol (PI) 4,5-biphosphate (PI(4,5)P2) hydrolysis and synthesis for B cell activation.
Purpose of the Study:
- To review molecular mechanisms of PI(4,5)P2-derived signaling amplification in B cells.
- To propose a "gasoline engine model" for B cell signaling activation.
- To discuss the universality and future prospects of this model.
Main Methods:
- Review of existing studies on PI(4,5)P2 signaling dynamics.
- Analysis of single-molecule diffusion of PI(4,5)P2.
- Conceptual modeling of B cell activation pathways.
Main Results:
- Antigen and B cell receptor (BCR) recognition reduces PI(4,5)P2 within microclusters, initiating positive feedback for PI(4,5)P2 synthesis.
- Slow PI(4,5)P2 diffusion maintains a density gradient, ensuring sustained supply to microclusters.
- A "gasoline engine model" is proposed, comparing B cell signaling activation to internal combustion.
Conclusions:
- The PI(4,5)P2 signaling amplification model provides a framework for understanding sustained B cell activation.
- The "gasoline engine model" offers a novel analogy for B cell signaling dynamics.
- Evidence suggests potential universality of this signaling mechanism across biological systems.