C. Oecking et al., THE FUSICOCCIN RECEPTOR OF PLANTS IS A MEMBER OF THE 14-3-3-SUPERFAMILY OF EUKARYOTIC REGULATORY PROTEINS, FEBS letters, 352(2), 1994, pp. 163-166
The receptor for the wilt-inducing phytotoxin fusicoccin was purified
to homogeneity from plasma membranes of Commelina communis as a comple
x with the radioligand [H-3]9'-nor-8'-hydroxyfusicoccin. The preparati
on consisted of two polypeptides with apparent molecular masses of 30.
5 kDa and 31.5 kDa and with isoelectric points of around pH 5.2 and 5.
3, respectively. The proteins were N-terminally blocked. Internal amin
o acid sequences were obtained for both polypeptides of the fusicoccin
-binding complex. Sequence information, as well as subsequent immunolo
gical analysis, proved that both polypeptides are members of the eukar
yotic 14-3-3 family, which comprises structurally conserved regulatory
proteins of widespread occurrence and a wide range of functions. 14-3
-3 isoform(s) constituting the fusicoccin receptor are distinguishable
from other cellular 14-3-3 proteins by their tight association with t
he plasma membrane. Applying temperature-induced Triton X-114 phase se
paration experiments, they, as well as the target enzyme of fusicoccin
action, the H+-ATPase, partitioned into the phospholipid-rich fractio
n which contains the most hydrophobic proteins. The results discussed
herein provide a basis for the elucidation of the molecular mechanism
of fusicoccin action.