Here's my problem. I ran human diabetic kidney extracts on a 7.5% native gel to test whether my protein is complexed with other protein or not. the result showed that my protein was forming complex with collagen type I and fibronectin. I showed the result to my PI and he questioned that how do i know if the complex ( my protein- collagen tpye I and fibronectin) was formed in vivo and not after making kidney extracts. So can anyone tell me is there a way to test whether the complex is formed in solution whlile making extracts or its formed in vivo which is what i am expecting...plzzzzz help!!!