Annexin I is a stress protein induced by heat, oxidative stress and a sulfhydryl-reactive agent.

Annexin I (also called lipocortin 1) is a 37-kDa member of the annexin family of proteins. It has been proposed to be involved in the regulation of cell growth and differentiation, apoptosis, and inflammation. Previously, we have reported that annexin I displays a chaperone-like function (Kim, G.Y., Lee, H.B., Lee, S.O., Rhee, H.J. & Na, D.S. (1997) Biochem. Mol. Biol. Int. 43, 521-528). To determine the possibility that annexin I is a stress protein, we examined whether expression of annexin I and annexin I mRNA increases in response to stresses in A549 and HeLa cells. Treatments of cells with heat, hydrogen peroxide or sodium arsenite resulted in (a) an increase in annexin I and annexin I mRNA and (b) translocation of annexin I from the cytoplasm to the nucleus and perinuclear region. The annexin I gene promoter region, cloned upstream of a reporter gene, was inducible in response to heat, hydrogen peroxide, and sodium arsenite. These results indicate that annexin I serves as a stress protein and annexins may constitute a new class of stress proteins.