Requirement for Rictor in homeostasis and function of mature B lymphoid cells

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• The mammalian target of rapamycin (mTOR) is a key kinase regulating cell processes.
• mTOR functions in distinct complexes (mTORC1 and mTORC2), but their roles in B cells are unclear.
• mTORC1 contains Raptor; mTORC2 contains Rictor and SIN1.

Purpose of the Study:

• To investigate the role of Rictor in B cell homeostasis and function.
• To determine how Rictor influences B cell survival, proliferation, and antibody responses.

Main Methods:

• Conditional deletion of Rictor in mice at different developmental stages.
• Analysis of B cell populations, antibody production, and gene expression.
• Assessment of signaling pathways, including nuclear factor κB (NF-κB).

Main Results:

• Rictor is required for the generation of mature B cell subsets (follicular, marginal zone, B1a).
• Rictor inactivation in adult mice impairs B cell homeostasis and antibody responses.
• Rictor is crucial for B cell survival by regulating prosurvival and proapoptotic genes.
• Rictor is vital for NF-κB induction following B-cell receptor stimulation and B-cell activating factor (BAFF) signaling.

Conclusions:

• mTOR signaling, specifically via Rictor, is critical for mature B lymphocyte survival and proliferation.
• Rictor acts as a key signal transducer in B cell homeostasis, development, and function.
• These findings highlight Rictor as a potential therapeutic target in B cell-related diseases.