Stathmin in mung bean leaves and rat brain.

Stathmin is a highly-conserved, cytosolic protein whose synthesis and phosphorylation is closely associated with growth and differentiation. Although conserved among vertebrates, stathmin has not been identified in plants. In the present study, anti-stathmin antibodies were generated against a synthetic peptide corresponding to amino-acid residues 32-44 of rat stathmin, and these antibodies were used to probe immunoblots of proteins from rat brain and mung bean. The antibodies recognized 12-kDa, 21-kDa and 22-kDa proteins in cytosolic fractions from mung bean leaves and a 12-kDa protein in cytosolic fractions from roots. The two larger proteins identified by the antibodies have apparent molecular weights and isoelectric points similar to those of rat brain stathmin. These results are the first to show that stathmin-like proteins are present in plants.