New research has identified MAP4K2 as a key regulator of regulatory T cells (Tregs), offering a new way to control the immune system in both cancer and autoimmune diseases.
The study shows that MAP4K2 controls the production of FOXP3, a protein essential for turning regular T cells into suppressive Tregs. It does this by interacting with another protein, DDX39B, and modifying it through phosphorylation. This process allows DDX39B to enter the cell nucleus and help process FOXP3-related RNA. Without this step, T cells cannot develop into fully functional Tregs.
In cancer, Tregs often protect tumors by weakening the immune response. Researchers found that removing MAP4K2 in mice led to smaller pancreatic tumors. Blocking MAP4K2 also made immunotherapy, such as anti–PD-1 treatment, more effective. In human pancreatic cancer, higher MAP4K2 levels in tumor-infiltrating Tregs were linked to more advanced disease.
However, the same pathway plays the opposite role in autoimmune disease. In a model similar to multiple sclerosis, mice without MAP4K2 developed more severe symptoms because their Tregs could not control immune attacks on healthy tissue.
These findings suggest that MAP4K2 could be a valuable drug target. Inhibiting it may boost immune responses against cancer, while activating it could help treat autoimmune diseases by strengthening immune regulation.