3-Indoleacrylic acid (IAA) is a natural auxin from lentil roots. 3-Indoleacrylic acid (IAA) induces transcription of genes under the control of the trpE promoter, including a family of proteins that contain nuclear localization signals. IAA also transcriptionally activates gene expression in plants. Trans-beta-Indoleacrylic acid (IAA) binds with moderately high affinity to the dimeric protein, trp aporepressor from Escherichia coli. 3-Indoleacrylic acid inhibits the growth of mycelia of Neurospora crassa and causes the cells to accumulate indoleglycerol phosphate.