The heat shock/stress response is characterized by the induction of several highly evolutionarily conserved
proteins during thermal stress, chemical stress, or
glucose starvation. It has recently been recognized that members of the
stress protein family are synthesized constitutively and subserve functions that are critical to protein folding during intracellular transport. In this study we examined the expression of heat shock/stress
proteins in human mononuclear phagocytes, cells dependent on intracellular transport for Ag processing, Ag presentation, generation of
reactive oxygen intermediates, and secretion of proinflammatory and antiinflammatory
polypeptides. The results indicate that there are distinct patterns in expression of individual members of the highly homologous SP70, SP90, and
ubiquitin gene families during different stress states. There is a marked increase in expression of the heat-inducible form of SP70 and SP90 in human monocytes during heat shock. Expression of GRP 78/BiP and GRP 94 increases predominantly during
glucose starvation but also increases during heat shock.
Ubiquitin gene expression increases during both heat shock and
glucose starvation. There is no change in synthesis of the constitutive form of SP 70 or of the
ubiquitin activating enzyme E1 during heat shock or
glucose starvation. Synthesis of the constitutive form of SP 70 and novel SP 90-like
polypeptides increase during
endotoxin-mediated inflammatory activation. One intracellular transport process of the mononuclear phagocyte, secretion of specific proinflammatory and antiinflammatory
polypeptides, is affected by
glucose starvation and by heat shock.