A dual role for receptor-interacting protein kinase 2 (RIP2) kinase activity in nucleotide-binding oligomerization domain 2 (NOD2)-dependent autophagy.
Autophagy is triggered by the intracellular bacterial sensor NOD2 (nucleotide-binding, oligomerization domain 2) as an anti-bacterial response. Defects in autophagy have been implicated in Crohn's disease susceptibility. The molecular mechanisms of activation and regulation of this process by NOD2 are not well understood, with recent studies reporting conflicting requirements for RIP2 (receptor-interacting protein kinase 2) in autophagy induction. We examined the requirement of NOD2 signaling mediated by RIP2 for anti-bacterial autophagy induction and clearance of Salmonella typhimurium in the intestinal epithelial cell line HCT116. Our data demonstrate that NOD2 stimulates autophagy in a process dependent on RIP2 tyrosine kinase activity. Autophagy induction requires the activity of the mitogen-activated protein kinases MEKK4 and p38 but is independent of NFκB signaling. Activation of autophagy was inhibited by a PP2A phosphatase complex, which interacts with both NOD2 and RIP2. PP2A phosphatase activity inhibited NOD2-dependent autophagy but not activation of NFκB or p38. Upon stimulation of NOD2, the phosphatase activity of the PP2A complex is inhibited through tyrosine phosphorylation of the catalytic subunit in a process dependent on RIP2 activity. These findings demonstrate that RIP2 tyrosine kinase activity is not only required for NOD2-dependent autophagy but plays a dual role in this process. RIP2 both sends a positive autophagy signal through activation of p38 MAPK and relieves repression of autophagy mediated by the phosphatase PP2A.
Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.
Craig R
CR
Homer
Amrita
A
Kabi
Noemí
N
Marina-García
Arun
A
Sreekumar
Alexey I
AI
Nesvizhskii
Kourtney P
KP
Nickerson
Arul M
AM
Chinnaiyan
Gabriel
G
Nuñez
Christine
C
McDonald
D001343:Autophagy; D004789:Enzyme Activation / Q000235:genetics; D004847:Epithelial Cells / Q000378:metabolism* / Q000382:microbiology; D057809:HEK293 Cells; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000382:microbiology; D048768:MAP Kinase Kinase Kinase 4 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics / Q000378:metabolism*; D054648:Protein Phosphatase 2 / Q000235:genetics / Q000378:metabolism; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2 / Q000235:genetics / Q000378:metabolism*; D012480:Salmonella Infections / Q000235:genetics / Q000378:metabolism; D012486:Salmonella typhimurium; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism
D016328:NF-kappa B; C429018:NOD2 protein, human; D053473:Nod2 Signaling Adaptor Protein; C506253:RIPK2 protein, human; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; D048051:p38 Mitogen-Activated Protein Kinases; D048768:MAP Kinase Kinase Kinase 4; C482779:MAP3K4 protein, human; D054648:Protein Phosphatase 2