Fusicoccin

Fusicoccin is a phytotoxin originally isolated from F. amygdali that induces death of tomato plants when used at concentrations ranging from 0.1 to 0.2 μg/ml. Topical administration of fusicoccin to tobacco (N. tabacum), sorghum (S. bicolor), cucumber (C. sativa), lucerne (M. sativa), and pokeweed (P. Americana) induces permanent opening of leaf stomata and wilting. Fusicoccin binds to the preformed complex between plasma membrane H+-ATPase and a 14-3-3 protein in plants to stabilize and activate the enzyme leading to dysregulated solute transport and control of transmembrane electric potential. It also stabilizes eukaryotic 14-3-3 protein interactions with binding partners containing a C-terminal 14-3-3 recognition motif, also known as a mode 3 motif, such as ERα, GPIbα, TASK3, CTFR, and p53 in vitro. Fusicoccin stimulates cortical neurite outgrowth in a 14-3-3 protein-dependent manner (EC50 = 29 μM). In vivo, topical administration of fusicoccin to the injury site reduces collapse and retraction of severed axons in a mouse model of spinal cord injury.