fgMM09

I'm at the end of my studies and I'm doing a research project for a couple of months. My project is based on a publication that showed that a certain F-box protein, which is part of the Cullin-RING ligase 1 or SCF1 complex, is the E3 ligase of a certain protein and promotes its proteasome-dependent degradation. I did CoIPs that showed a strong binding of both proteins. However I couldn't detect an effect of the E3 ligase on the protein, neither ubiquitynation nor degradation. I think that the protein I'm working with is not a substrate of this E3 ligase but since I can detect a strong binding I would like to know what effect this E3 ligase on the protein has. I'm running out of ideas what experiments I could further do. Any recommendations? Thank you!