Pseudokinase STK40 promotes T<sub>H</sub>1 and T<sub>H</sub>17 cell differentiation by targeting FOXO transcription factors.

Tao, Yuexiao; Jiang, Zhenyan; Wang, Huizi; Li, Jia; Li, Xin; Ni, Jun; Liu, Jiamin; Xiang, Hongrui et al. · Sci Adv · 2024

basic_science · Level V

Where this comes from

Abstract

Inappropriate CD4<sup>+</sup> T helper (T<sub>H</sub>) cell differentiation leads to progression of inflammatory and autoimmune diseases, yet the regulatory mechanisms governing stability and activity of transcription factors controlling T<sub>H</sub> cell differentiation remain elusive. Here, we describe how pseudokinase serine threonine kinase 40 (STK40) facilitates T<sub>H</sub>1/T<sub>H</sub>17 differentiation under pathological conditions. STK40 in T cells is dispensable for immune homeostasis in resting mice. However, mice with T cell-specific deletion of STK40 exhibit attenuated symptoms of experimental autoimmune encephalomyelitis and colitis, accompanied by diminished T<sub>H</sub>1 and T<sub>H</sub>17 cell differentiation. Mechanistically, STK40 facilitates K48-linked polyubiquitination and proteasomal degradation of FOXO1/4 through promoting their interaction with E3 ligase COP1. Inhibition of FOXO4 or FOXO1, respectively, restores differentiation potential of STK40-deficient T<sub>H</sub>1/T<sub>H</sub>17 cells. Together, our data suggest a crucial role of STK40 in T<sub>H</sub>1 and T<sub>H</sub>17 cell differentiation, thereby enabling better understanding of the molecular regulatory network of CD4<sup>+</sup> T cell differentiation and providing effective targets for the treatment of autoimmune diseases.

Medical subject headings