Inconsistent results on protein intereations - (Dec/18/2004 )
My protein partners show interaction in yeast-two-hybrid and GST pull down assay, but not in Co-IP. Does anyone had this sort of problem before? What are the possible reseasons for that?
I had a similar problem with Co-IP. When using IP buffer, membrane structures and cytoskeleton remain in the debri, and not in solution. If interaction between the proteins requires intact membrane structures, you wont be able to co-IP the proteins usind standard protocols. Instead, you might want to do cell fractionation first, and then IP from the fractions (membrane, cytosol, etc).