A system for reconstructing B cell antigen receptor signaling in the mouse myeloma J558L cell line

Area of Science:

• Immunology
• Synthetic Biology
• Cell Signaling

Background:

• B cell antigen receptor (BCR) signaling is crucial for B cell function and is regulated by cell surface receptors like CD19 and CD45.
• Traditional gene targeting methods have limitations for simultaneously analyzing multiple signaling molecules.
• Synthetic biology offers a flexible approach for dissecting complex cellular signaling pathways.

Purpose of the Study:

• To develop and validate a novel system for reconstructing and analyzing BCR signaling using synthetic biology.
• To investigate the roles of CD19 and CD45 in BCR signaling kinetics.
• To identify novel proteins involved in BCR signaling.

Main Methods:

• Reconstruction of BCR signaling in the J558L myeloma cell line using the Ca(2+) indicator YC3.60.
• Co-expression of CD19 and CD45 in the J558Lμv11 cell line to monitor BCR-induced Ca(2+) mobilization.
• Proteomic analysis of tyrosine-phosphorylated proteins following antigen stimulation in the reconstituted system.

Main Results:

• The J558Lμv11 cell system successfully monitored BCR-induced Ca(2+) mobilization.
• CD19 and CD45 expression modulated BCR signaling kinetics differently.
• Proteomic analysis identified over 100 BCR-induced tyrosine-phosphorylated proteins, including the novel non-receptor tyrosine kinase Fer, with similarities to endogenous B cells.

Conclusions:

• The J558L cell-based reconstruction system is a valid and powerful tool for comprehensive investigation of BCR signaling.
• This system facilitates the discovery of novel components and regulatory mechanisms within BCR signaling pathways.
• The findings provide new insights into the complex regulation of B cell activation and function.