FIGURE 4.

Caprin-2 scaffolds the CDK14-Cyclin Y-LRP6 complex. A, HEK293T cells were transfected with CDK14-GFP and Cyclin Y-FLAG with or without 5HA-Caprin-2 as indicated. Cell lysates were then immunoprecipitated with anti-FLAG antibody, and the immunoprecipitates were probed with the indicated antibodies. B, HEK-293T cells were infected by a lentivirus encoding shRNAs of Caprin-2 for 48 h, and then cells were transfected with the indicated plasmids. Co-IP was performed as described in A. C, endogenous interaction of Caprin-2/CDK14/Cyclin Y increased at G₂/M. HeLa cells were synchronized by double thymidine block, and the cells lysates from G₁/S- or G₂/M-synchronized cells were immunoprecipitated by Cyclin Y-specific antibody, followed by Western blotting analysis with the indicated antibodies. D, endogenous Caprin-2/CDK14/Cyclin Y/LRP6 complexes were analyzed in HEK293 cells. Immunoprecipitation was performed with an anti-LRP6 polyclonal antibody. IgG was used as a control. Before co-immunoprecipitation, cells were treated with shCaprin-2 lentivirus for 56 h and nocodazole for another 16 h. E, model for Caprin-2 modulating constitutive LRP6 phosphorylation.