Are Ab's phosphorylated?

[Jim Woodgett]

In article <36d0p3$8ek at gazette.bcm.tmc.edu>, ah690549 at mbcr.bcm.tmc.edu 
(Annette C. Hollmann) writes:  
> In article <36cp86$3vu at agate.berkeley.edu> lhom at OCF.Berkeley.EDU 
> (Louis Hom) writes: 
> >I know antibodies are glycosylated, but are they phosphorylated? 

> Yes they are. I found that out the hard way while doing in 
> vitro phosphorylation experiments :-( 

I think he may mean in vivo and in that case the answer is no. The 
phosphorylation often (but not always) seen in immunoprecipitate kinase assays 
is an in vitro artefact due to the high level of IgG in proximity to the 
kinase. Essentially any protein containing Ser/Thr/Tyr can be phosphorylated 
in vitro if you push it hard enough. 

Jim