Transmembrane activator and CAML interactor

Transmembrane activator and CAML interactor (TACI), also known as TNFRSF13B, is a protein that in humans is encoded by the TNFRSF13B gene. TACI is a member of the tumor necrosis factor receptor superfamily. This protein plays a crucial role in B cell differentiation and immune response.

Structure

TACI is a type III transmembrane protein of the TNF receptor superfamily. It is characterized by the presence of two cysteine-rich domains in the extracellular region and a cytoplasmic region that is required for intracellular signaling. The protein is approximately 293 amino acids in length.

Function

TACI is primarily expressed on the surface of B cells, where it functions as a receptor for two ligands: BAFF (B-cell activating factor) and APRIL (a proliferation-inducing ligand). These ligands are crucial for the survival and differentiation of B cells. TACI also plays a role in the regulation of T cell-independent immune responses and is involved in the class switch recombination process in B cells.

Clinical significance

Mutations in the TNFRSF13B gene can lead to a condition known as Common Variable Immunodeficiency (CVID), which is characterized by low levels of serum immunoglobulins and an increased susceptibility to infections. Additionally, aberrant expression of TACI has been associated with autoimmune diseases such as Systemic Lupus Erythematosus (SLE) and Rheumatoid Arthritis (RA).

See also

• Tumor necrosis factor receptor
• B cell
• BAFF (B-cell activating factor)
• APRIL (a proliferation-inducing ligand)
• Common Variable Immunodeficiency
• Systemic Lupus Erythematosus
• Rheumatoid Arthritis

References

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