co-ip of endogenous and tagged proteins - (Jul/15/2013 )

hello everyone,

sorry for my simple basic question, but for studies and experiments, will it be enough to perform co-ip from endogenous proteins? why is it sometimes necessary to transfect his or gst-fused protein and then perform co-IP? is it only for validation? thank you...

Generally speaking, antibodies for the tag (ie 6His or FLAG or GFP) are more specific than the antibody against the targeted endogenous protein. Therefore, you should have less non-specific interactions with the antibody and then the IP should be cleaner.