Subcellular differences in post-translational modification of barley 14-3-3 proteins

Expression and post-translational modification of barley 14-3-3 isoforms, 1 4-3-3A, 14-3-3B and 14-3-3C, mere investigated using isoform-specific antib odies. Although all three isoforms were shown to be present in the cytosoli c, the nuclear and the microsomal cell fractions, differences in post-trans lational modification were identified for the different cell fractions. Ger mination-related modifications of 14-3-3 proteins mere observed in the cyto sol and the microsomal fraction, but not in the nucleus. In vitro proteolyt ic cleavage of 14-3-3 proteins using trypsin suggests that for 14-3-3A this change mas caused by proteolytic cleavage of the unconserved C-terminal re gion. (C) 2000 Federation of European Biochemical Societies.