Light response in plants: Nucleoside Diphosphate Kinase Sees the Light

Science's STKE  12 Oct 1999:
Vol. 1999, Issue 3, pp. tw5
DOI: 10.1126/stke.1999.3.tw5

Plants respond to red light through receptors known as phytochromes, but the signaling mechanisms that mediate cellular responses to activated phytochromes are not well understood. Choi et al. therefore used a yeast two-hybrid screen to identify proteins that bound to phytochrome A. They came up with nucleoside diphosphate kinase 2 (NDPK2), a protein that acts as a tumor suppressor in mammalian cells. Arapidopsis plants lacking NDPK2 were insensitive to red and far-red light. NDPK2 preferentially bound to light-activated phytochrome A in vitro and gamma-phosphate exchange activity of NDPK2 was increased as a consequence. NDPK has been ascribed a number of different activities in various cell types from transcription factor to activator of G proteins. Exactly how NDPK2 acts to promote responses of plant cells to red light remains a mystery.

Choi, G., Yi, H., Lee, J., Kwon, Y.-K., Soh, M.S., Shin, B., Luka, Z., Hahn, T.-R., and Song, P.-S. (1999) Phytochrome signalling is mediated through nucleoside diphosphate kinase 2. Nature 401: 610-613. [Online Journal]