Ecologically Relevant Variation in Induction and Function of Heat Shock Proteins in Marine Organisms

Ectothermic organisms often face dramatic traverses of environmental temperature on a daily or seasonal basis; exemplars among this group are invertebrates and fish of the rocky intertidal zone. Because of the extremes of temperature exposure, intertidal animals have served as an excellent study system to examine the expression of heat shock proteins (Hsps) in response to natural variation in environmental temperature. Ecologically relevant variation in Hsp expression has been observed with seasonal acclimatization, with small-scale temperature gradients that occur in microhabitats and between species with different intertidal distributions. The maturing understanding of Hsp expression patterns in marine organisms has established a solid foundation on which to build the next set of questions. In this paper, I present an overview of the variation of Hsp expression in intertidal animals in nature and then address two emerging areas of investigation in the ecological physiology of Hsps. One area addresses the plasticity of Hsp expression in marine invertebrates and focuses on the mechanism of regulation of Hsp gene expression by environmental temperature. A second emerging area of investigation concerns whether Hsps as molecular chaperones display functional diversity that correlates with species' adaptation temperature.