The DNA damage-induced transcription of this gene is mediated by both p53-dependent and -independent mechanisms.

The protein encoded by this gene responds to environmental stresses by mediating activation of the p38/JNK pathway via MTK1/MEKK4 kinase.

[7] The fact that expression of this gene is an indicator of DNA damage has been exploited to construct an in vitro test for mutagenicity, the GADD45a-GFP GreenScreen HC assay.

[8] This assay consists of a cell line which has been engineered so that expression of GADD45A will lead to expression of green fluorescent protein, which can easily be detected.

To test a substance for mutagenicity, it is applied to these cells and fluorescence is measured.