In a paper that will be published online in advance of its July 1st publication date, Drs. Niko Geldner, Joanne Chory and colleagues (The Salk Institute and HHMI) demonstrate that endosomes can function as signaling platforms in plants, as well as in animals.

"These findings will influence our thinking of the evolutionary origins of endosomes and hopefully help us to understand why cells use them as signaling compartments," noted lead author of the paper, Dr. Niko Geldner.

Endosomes were once thought to function solely in the inactivation of receptors and the down-regulation of cell signaling. Work in animal cells over the past several years has shown that receptor endocytosis can actually facilitate signaling through the cell, by bringing signaling components in contact with their activated receptors.

Drs. Geldner, Chory and collaborators now extend the range of endosome-mediated signaling into the plant kingdom. The researchers show that the growth-promoting brassinosteroid receptor (BRI1) is trafficked through endosomes to enhance activation of this growth response pathway, which affects both shoot and root growth.

Dr. Chory is hopeful that these results will serve as a springboard for future studies aimed at unraveling the mechanics of how plants grow."