To Paul Goodwin,
    There are not many antibodies capable of differentiating bewteen
phosphorylated and non-phosphorylated forms of a protein. NEB has started
making ab specifically against phosphorylated (i.e activated) extracellular
signal-regulated kinases (ERKs), and against phosphorylated p34cdc2, which
theoretically could be used for confocal studies. Some labs have also made
antibodies against activated kinases such as ZAP70 and CKII, activation
occurring in response to phosphorylation, but I have yet to hear of these
abs being used for confocal studies.