Abstract
The diversity of organisms arises through adaptation to the environment. Thus, how organisms have evolved and diversified may be understood by studying the diversity of organism's defense mechanisms against environmental stresses.
In this presentation, I will discuss about cyanobacterial responses to environmental changes such as temperature and nutrient availability, by focusing on functions of molecular chaperones. We have shown that molecular chaperones play important roles in acquisition of tolerance to various stresses. Through these studies, we started to think that light-harvesting phycobilisomes may be one of the major targets for molecular chaperones. Intriguingly, HtpG, a homolog of Hsp90, from E. coli, the model heterotrophic organism, did not protect components of phycobilisomes at high temperatures, although its cyanobacterial counterpart did. The results may indicate that cyanobacterial HtpG has evolved to interact with phycobilisomes in order to sustain photoautotrophic life.
