Fig. 6

circbabo(5,6,7,8S)-p dampens TGF-β signaling by interfering with babo/put receptor heterodimerization. A Flies carrying the cg-Gal4 driver were crossed to shGFP (control) or shcircbabo(5,6,7,8S) flies. Immunoblot analysis of fat bodies of the indicated genotypes shows that levels of pSmad are elevated upon circbabo(5,6,7,8S) depletion. Tubulin serves as a loading control. B Levels of pSmad are decreased in the fat bodies of cg > Flag-circbabo(5,6,7,8S)-p flies, and elevated in fat bodies overexpressing babo.Q302D. Tubulin serves as a loading control. C Flag tagged circbabo(5,6,7,8S)-p could pull-down HA tagged babo. Various combinations of expression constructs for Flag-tagged circbabo(5,6,7,8S)-p and HA-tagged babo were transfected into S2 cells. Both 10% of cell lysates and immuno-purified HA and Flag complexes were analyzed by immunoblot. D Flag tagged circbabo(5,6,7,8S)-p could pull-down HA tagged put. Various combinations of expression constructs for Flag-tagged circbabo(5,6,7,8S)-p and HA-tagged put were transfected into S2 cells. Both 10% of cell lysates and immuno-purified HA and Flag complexes were analyzed by immunoblot. E circbabo(5,6,7,8S)-p and Smad did not interact with each other. Various combinations of expression constructs for Flag-tagged circbabo(5,6,7,8S)-p and HA-tagged Smad were transfected into S2 cells. Both 10% of cell lysates and immuno-purified HA and Flag complexes were analyzed by immunoblot. F circbabo(5,6,7,8S)-p interferes with babo/put receptor heterodimerization. Various combinations of expression constructs for Flag-tagged circbabo(5,6,7,8S)-p, Flag-tagged put and HA-tagged babo were transfected into S2 cells. Both 10% of cell lysates and immuno-purified HA complexes were analyzed by immunoblot. G Quantification of the ratio of Flag-put/HA-babo intensity in the immuno-purified HA complexes as shown in F. The experiment has been repeated 3 times (student t-test, ***p < 0.001)