NIMA-related kinase 9–mediated phosphorylation of the microtubule-associated LC3B protein at Thr-50 suppresses selective autophagy of p62/sequestosome 1
Permanent lenke
https://hdl.handle.net/10037/17952Dato
2019-12-19Type
Journal articleTidsskriftartikkel
Peer reviewed
Forfatter
Shrestha, Birendra Kumar; Rasmussen, Mads Skytte; Abudu, Yakubu Princely; Bruun, Jack-Ansgar; Larsen, Kenneth Bowitz; Alemu, Endalkachew Ashenafi; Sjøttem, Eva; Lamark, Trond; Johansen, TerjeSammendrag
Human ATG8 family proteins (ATG8s) are active in all steps of the macroautophagy pathway, and their lipidation is essential for autophagosome formation. Lipidated ATG8s anchored to the outer surface of the phagophore serve as scaffolds for binding of other core autophagy proteins and various effector proteins involved in trafficking or fusion events, whereas those at the inner surface are needed for assembly of selective autophagy substrates. Their scaffolding role depends on specific interactions between the LC3-interacting region (LIR) docking site (LDS) in ATG8s and LIR motifs in various interaction partners. LC3B is phosphorylated at Thr-50 within the LDS by serine/threonine kinase (STK) 3 and STK4. Here, we identified LIR motifs in STK3 and atypical protein kinase Cζ (PKCζ) and never in mitosis A (NIMA)-related kinase 9 (NEK9). All three kinases phosphorylated LC3B Thr-50 in vitro. A phospho-mimicking substitution of Thr-50 impaired binding of several LIR-containing proteins, such as ATG4B, FYVE, and coiled-coil domain-containing 1 (FYCO1), and autophagy cargo receptors p62/sequestosome 1 (SQSTM1) and neighbor of BRCA1 gene (NBR1). NEK9 knockdown or knockout enhanced degradation of the autophagy receptor and substrate p62. Of note, the suppression of p62 degradation was mediated by NEK9-mediated phosphorylation of LC3B Thr-50. Consistently, reconstitution of LC3B-KO cells with the phospho-mimicking T50E variant inhibited autophagic p62 degradation. PKCζ knockdown did not affect autophagic p62 degradation, whereas STK3/4 knockouts inhibited autophagic p62 degradation independently of LC3B Thr-50 phosphorylation. Our findings suggest that NEK9 suppresses LC3B-mediated autophagy of p62 by phosphorylating Thr-50 within the LDS of LC3B.
Forlag
American Society for Biochemistry and Molecular BiologySitering
Shrestha BK, Rasmussen MS, Abudu YP, Bruun JA, Larsen KBL, Alemu EA, Sjøttem E, Lamark T, Johansen T. NIMA-related kinase 9–mediated phosphorylation of the microtubule-associated LC3B protein at Thr-50 suppresses selective autophagy of p62/sequestosome 1 . Journal of Biological Chemistry. 2019Metadata
Vis full innførselSamlinger
Copyright 2019 The American Society for Biochemistry and Molecular Biology, Inc.