The inflammation repressor TNIP1/ABIN-1 is degraded by autophagy following TBK1 phosphorylation of its LIR.

Abstract

The inflammatory repressor TNIP1/ABIN-1 is important for keeping in check inflammatory and cell-death pathways to avoid potentially dangerous sustained activation of these pathways. We have now found that TNIP1 is rapidly degraded by selective macroautophagy/autophagy early (0-4 h) after activation of TLR3 by poly(I:C)-treatment to allow expression of pro-inflammatory genes and proteins. A few hours later (6 h), TNIP1 levels rise again to counteract sustained inflammatory signaling. TBK1-mediated phosphorylation of a TNIP1 LIR motif regulates selective autophagy of TNIP1 by stimulating interaction with Atg8-family proteins. This is a novel level of regulation of TNIP1, whose protein level is crucial for controlling inflammatory signaling.