Abstract
Plants have evolved several informational photoreceptors, of which the phytochromes are specialized in perceiving red and far-red region of the spectrum. Phytochrome is a soluble chromoprotein and its polypeptide has two domains: the N-terminal light-sensing moiety and the C-terminal moiety with a kinase motif. Although the C-terminal moiety had been believed to be involved in signal transduction, it has recently been shown that the N-terminal moiety, but not the C-terminal moiety, transduces the signal to downstream components, which forces us to reconsider our view on phytochrome signaling. Recently, through a genetic screen, we found a cluster of residues necessary for signal transduction, in a small region within the N-terminal moiety. In this talk, the initial events of phytochrome signaling will be discussed in relation to the intramolecular structure of phytochrome.
