Immunoprecip gurus?

[Dima Klenchin]

:Ok, let's say protein A binds to protein B which binds to protein C.  If
:I pull down with an antibody to protein C (from cell lysates), should I
:expect to be able to pull down protein A with it and probe for protein A
:on a Western, or is it too much to hope for that everthing will stay
:together during the IP?  I'm sure it depends on dissociation contants,
:but generally speaking...
:
:Are magnetic beads more effiecient than Protein A Sepharose beads?

My experience with IP is that if one tries really hard, it is possible
to co-IP anything with anything. Particularly when a criterion for 
co-IP is a sensitive western. And that is the major problem with
this overused undervalidated technique.

        - Dima