A novel Argonaute 2-Niche at the midzone is essential for Cell-division integrity

AGO2 is an indispensable component of the RNA-induced silencing complex (RISC), operating at the transcriptional or posttranscriptional level. It is compartmentalized into the nucleus and the cytoplasm, in structures such as GW- and P-bodies, stress granules and adherens junction. In our study, immunofluorescence assays, image and bioinformatic analysis and cytogenetics demonstrated that AGO2 also resides in protrusional structures: open- and close-ended tubes. The latter are cytokinetic bridges where AGO2 colocalizes at the midbody-arms with crucial cytoskeletal components such as α-Τubulin and Aurora B, and various kinases. Phosphorylated AGO2 (Ser387), together with Dicer, is located at the midbody ring in a p38-dependent manner probably supporting its known function in these unexpected sites. We also reported the stress-responsive nature of AGO2 and its important role during cell division, ensuring the proper chromosome segregation and cytokinetic fidelity. In conclusion, AGO2 is implicated in a regulatory mechanism triggered by cytokinetic stress in order to generate a niche and the appropriate micro-environment for local-transcript homeostasis. <br> Statement: AGO2 resides in open-ended tunneling nanotubes and close-ended cytokinetic bridges. In the latter, it is implicated in a regulatory mechanism triggered by cytokinetic stress in order to generate a niche and the appropriate microenvironment for, most likely, local-transcript homeostasis.