Immediate early response gene 5 protein (Ier5)

Mediates positive transcriptional regulation of several chaperone gene during the heat shock response in a HSF1-dependent method. Mediates negative transcriptional regulation of CDC25B expression.

Plays a role in the dephosphorylation of the heat shock factor HSF1 and ribosomal protein S6 kinase (S6K) by the protein phosphatase PP2A. Involved in the regulation of cell proliferation and resistance to thermal stress.