Recently, Richter et al. [1] revealed the potential functions of the interaction between the serine/threonine kinase Tank-binding kinase 1 (TBK1) and the autophagy receptor optineurin (OPTN). The TBK1-OPTN axis targets damaged mitochondria for degradation via PINK1/parkin-mediated mitophagy [2, 3]. Indeed, TBK1 can phosphorylate OPTN at Ser177, Ser473, or Ser513 to enhance the binding capacity of OPTN with poly-ubiquitin (poly-UB) chains. Conversely, binding of poly-UB chains to OPTN is essential for the efficient recruitment and activation of ...