The TBK1 adaptor and autophagy receptor NDP52 restricts the proliferation of ubiquitin-coated bacteria.
Cell-autonomous innate immune responses against bacteria attempting to colonize the cytosol of mammalian cells are incompletely understood. Polyubiquitylated proteins can accumulate on the surface of such bacteria, and bacterial growth is restricted by Tank-binding kinase (TBK1). Here we show that NDP52, not previously known to contribute to innate immunity, recognizes ubiquitin-coated Salmonella enterica in human cells and, by binding the adaptor proteins Nap1 and Sintbad, recruits TBK1. Knockdown of NDP52 and TBK1 facilitated bacterial proliferation and increased the number of cells containing ubiquitin-coated salmonella. NDP52 also recruited LC3, an autophagosomal marker, and knockdown of NDP52 impaired autophagy of salmonella. We conclude that human cells utilize the ubiquitin system and NDP52 to activate autophagy against bacteria attempting to colonize their cytosol.
Thurston
Teresa L M
TL
Medical Research Council Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Cambridge, UK.
Ryzhakov
Grigory
G
Bloor
Stuart
S
von Muhlinen
Natalia
N
Randow
Felix
F
D048868:Adaptor Proteins, Signal Transducing / Q000276:immunology / Q000378:metabolism; D000595:Amino Acid Sequence; D001343:Autophagy; D006367:HeLa Cells; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000276:immunology / Q000378:metabolism; D011506:Proteins / Q000276:immunology / Q000378:metabolism; D034622:RNA Interference; D012480:Salmonella Infections / Q000276:immunology; D019779:Salmonella enterica / Q000276:immunology*; D025801:Ubiquitin / Q000276:immunology* / Q000378:metabolism; D054875:Ubiquitination; D012359:tRNA Methyltransferases
D048868:Adaptor Proteins, Signal Transducing; C094297:CALCOCO2 protein, human; C477012:MAP1LC3A protein, human; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D011506:Proteins; C524349:TBKBP1 protein, human; D025801:Ubiquitin; C498548:TRMO protein, human; D012359:tRNA Methyltransferases; D017346:Protein Serine-Threonine Kinases; C403191:TBK1 protein, human