Heat-shock proteins (Hsp’s) are an essential part of a cells defence against many different environmental stresses. However, an article by Pigluicci suggests that they can also act as a genetic buffer, protecting the organism by preventing the expression of mutations in the genome.The article by Cowen and Lindquist shows that fungi can acquire drug resistance after Hsp’s are disrupted. In many cases this was due to the drug’s target protein being denatured by environmental stress and the Hsp not refolding it correctly, causing the drug not to recognize and bind the protein. However, in some cases the acquisition of drug resistance was due to genetic variation which had previously been prevented from being expressed by the Hsp’s. Cowen and Lindquist concluded that Hsp’s have the capacity to buffer the expression of genetic and epigenetic variation and to release it in response to environmental stress.
However, although this acquisition of drug resistance should increase an organism’s fitness to survive, the disruption of the Hsp’s will most likely also cause other important proteins, for example proteins necessary for metabolism, to fold incorrectly and lose function.
References
Secondary Reference – Pigluicci, M (6 June, 2002) Buffer Zone. Nature. Vol. 417. 598-599
Topic: Directed Mutations (Heat-shock Proteins)
