I am now studying a protein, this protein might affects cell proliferation because I performed a Knock down experiment and I found that the cells proliferation rate is reduced when this protein is knocked-down. This protein is a trafficking protein which has role in transport from ER - Golgi, I suspect that the mechanism related to this reduced proliferation rate is because of the delayed cargo shipment to golgi. What method is used to identify the cargo protein of this protein ? I want to collect many materials before I spoke to my PI