Group of proteins whose synthesis is increased by increased transcription when cells are exposed to elevated temperatures.

Note: Production of high levels of heat shock proteins can also be triggered by exposure to different kinds of environmental stress conditions, e.g., infection, inflammation, exposure of the cell to chemicals (such as ethanol, arsenicals, or certain metal species), ultraviolet light, starvation, hypoxia (oxygen deprivation), nitrogen deficiency (in plants), or water deprivation. Hence, the alternative name, stress proteins. Their upregulation is sometimes described more generally as part of the stress response.