The stress response is highly conserved cellular response from prokaryotes to eukaryotes that is associated with the synthesis of stress proteins or heat shock proteins (Hsps). Hsps form the most ancient defense system in all living organisms on earth. These proteins function as molecular chaperones helping in protein folding, assembly, translocation and degradation. Available information on Hsps suggests that in addition to their cytoprotective roles upon stress, Hsps are required for the normal cellular functions such as development, differentiation, cell cycle, signal transduction and many more. While the beneficial effects of Hsps under normal physiological conditions and upon stress are gaining interest, cellular adaptations and civilization-associated diseases, including cancers, are associated with high expression of Hsps contributing to disease progression. Hsps are also involved in epigenetic regulation and phenotypic evolution. Therefore considering the multitudes of involvement in various cellular processes, Hsps are considered as molecular markers and pharmacological targets for different disease and pathological models. Here, we review Hsps involvement in biology and medicine, and discuss future perspectives of Hsps research.

At cellular level all organisms respond to a large variety of unfavorable (stress) conditions, which are categorized under three major headingsenvironmental, pathophysiological, and intracellular stress. Stress induces acceleration of transcription of a set of genes called, heat shock genes. Heat shock proteins (Hsps) are the translational products of these genes, present in cells under normal physiological conditions, however, at low amounts, increases upon stress to manifold (Morimoto et al., 1997). These proteins gained significance due to their selective synthesis upon stress, when all other transcription machinery either slowed or shut down. Hsps are ubiquitously expressed in all cells under normal physiological conditions and are highly conserved among species. The constitutive expression of Hsps under normal physiological conditions serves cells in maintaining the normal cellular homeostasis directly associating with various molecules of central cellular machinery.

Perturbation of normal gene expression during stress response may lead to fatal consequences, such as altered RNA processing, RNA stability and translation, transcriptional termination, ribosomal export and import, malfunction of golgi and severe alterations in the cytoarchitecture, cellular homeostasis, and membrane dynamics. Therefore, stress has a gross cellular impact by inhibiting several cellular processes; consequently, induction of stress proteins or heat shock proteins may have cytoprotective effects. Unlike many other genes, heat shock genes are intronless, hence the transcription and translation of these genes are achieved in the shortest time possible. Further, Hsp mRNA is stabilized after stress resulting in continued synthesis of Hsps, thereby eliciting a prolonged stress response (Granelli-Piperno et al., 1986; Theodorakis and Morimoto, 1987; and Morimoto et al., 1990). Hsps having chaperoning functions accomplishes the demands of intra cellular stress and thus helps in cell recovery on exposure to stress.

Stress Response and Emerging Roles, Heat Shock Proteins, Molecular Chaperones, Prokaryotes, Eukaryotes, Pathophysiological, Intracellular stress, Cytoarchitecture, Cellular homeostasis, Pharmacological Interventions, pharmacological explorations, Posttranscriptional Regulations.