Cold-shock proteins

Change in temperature is one of the most common stresses faced by all living organisms. Microorganisms, which encounter significant shifts to either high or low temperatures in their natural habitats, are equipped with cellular mechanisms to respond and adapt to these changes. The focus of research in previous years had been heat shock response and adaptation, as heat shock causes well-defined changes in cell such as protein unfolding. On the other hand, effect of cold shock was thought to be more of a general nature, for example slowing down of metabolic activities. Recent observations have changed this outlook on cold-shock response and shown it to be a specific response of cell at various levels such as cytoplasmic membrane, ribosomes, nucleic acids, and proteins. Cold-shock proteins are induced upon temperature downshift and play a significant role in acclimation of cells to cold (for reviews, see Yamanaka et al. 1998; Phadtare et al. 1999, 2000; Ermolenko and Makhatadze 2002; Weber and Marahiel 2003; Phadtare 2004). In this chapter, we describe salient features of bacterial cold-shock response and cold-shock proteins.