Abstract
T cells are essential for defense of the host against invading pathogens. Antigen activation of the T cell receptor (TCR) is required for generation of an adaptive immune response. Several groups have observed that blocking autophagy augments T cell activation, but the molecular basis of this finding has remained elusive. The adaptor protein BCL10 transmits activating signals from the TCR to NFKB1-RELA/NFκB, a transcription factor that is critical for T cell proliferation and function. We recently reported that a TCR-dependent autophagy mechanism selectively targets and degrades BCL10. We found that BCL10 autophagy requires BCL10 K63-polyubiquitination and subsequent binding to the autophagy adaptor SQSTM1/p62. Blocking either one of these processes inhibits BCL10 degradation. Protecting BCL10 from autophagic degradation, either by pharmacological or genetic inhibition of autophagy, results in increased activation of NFKB1-RELA. By demonstrating the mechanism of autophagic uptake and degradation of BCL10, our study has revealed a key mechanism by which selective autophagy controls T cell activation. Here, we discuss the implications of our findings and explore possible directions for future research.
Acknowledgments
Supported by grants from the National Institutes of Health (AI057481 to B.C.S.), the Center for Neuroscience and Regenerative Medicine (CNRM) (to B.C.S.), and a predoctoral fellowship (to S.P.) from the American Heart Association.