RESUMEN
A coding allele of ATG16L1 that increases the risk of Crohn disease (T300A; rs2241880) impairs the interaction between the C-terminal WD40 domain (WDD) and proteins containing a WDD-binding motif, thus specifically inhibiting the unconventional autophagic activities of ATG16L1. In a recent publication we described a novel atypical role of ATG16L1 in the regulation of IL10R (interleukin 10 receptor) trafficking and signaling, an activity that involves direct interaction between the WDD and a target motif present in IL10RB (interleukin 10 receptor subunit beta). Here we show that, unexpectedly, neither the ability of ATG16L1 to interact with IL10RB nor its role in supporting IL10 signaling are altered by the T300A mutation. These results indicate that the ATG16L1T300A allele selectively impairs the interaction between the WDD and a subset of WDD-binding motif versions, suggesting that only a fraction of the unconventional activities mediated by ATG16L1 are required to prevent Crohn disease.Abbreviations: ATG, autophagy related; ATG16L1, autophagy related 16 like 1; BMDMs, bone marrow-derived macrophages; CRISPR, clustered regularly interspaced short palindromic repeats; CSF1/M-CSF, colony stimulating factor 1; FBS, fetal bovine serum; GSH, glutathione; IL10, interleukin 10; IL10R, interleukin 10 receptor; LPS, lipopolysaccharide; MAP1LC3/LC3, microtubule associated protein 1 light chain 3; MEFs, mouse embryonic fibroblasts; PMA, phorbol myristate acetate; p-STAT3: phosphorylated STAT3; qPCR, quantitative polymerase chain reaction; SDS, sodium dodecyl sulfate; sgRNA, single guide RNA; TMEM59, transmembrane protein 59; TNF, tumor necrosis factor; TNFAIP3/A20, TNF alpha induced protein 3; WDD, WD40 domain; WIPI2, WD repeat domain, phosphoinositide interacting 2.
Asunto(s)
Proteínas Relacionadas con la Autofagia , Enfermedad de Crohn , Receptores de Interleucina-10 , Repeticiones WD40 , Autofagia/genética , Proteínas Relacionadas con la Autofagia/metabolismo , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Enfermedad de Crohn/genética , Enfermedad de Crohn/metabolismo , Interleucina-10/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Receptores de Interleucina-10/metabolismo , Repeticiones WD40/genética , HumanosRESUMEN
ATG16L1 is a critical mediator of macroautophagy/autophagy required for LC3 lipidation and autophagosome formation. However, ATG16L1 has a C-terminal domain including 7 WD40-type repetitions (WD40 domain, WDD) that is unnecessary for the conventional autophagic pathway. Instead, this domain mediates unconventional activities where LC3 is lipidated in atypical subcellular localizations unrelated to canonical double-membrane autophagosomes. The WDD provides a docking surface for molecules including a specific amino acid motif, thus engaging the LC3 lipidation capabilities of ATG16L1 in single-membrane structures. The physiological implications of such atypical activities are poorly characterized. In a recent report we described the improvement of the WDD-binding motif and the identification of transmembrane molecules that harbor this element in their intracellular region. One of them, IL10RB (interleukin 10 receptor subunit beta), binds the WDD after IL10 activation to facilitate endocytosis, early trafficking and signaling of IL10-IL10R complexes without influencing their degradation rate. These results reveal a novel unconventional role of ATG16L1 in cytokine signaling that does not entail a degradative purpose, thus contributing to catalog the physiological roles played by unconventional activities of the autophagic machinery.