Atypical and probable non DNA-binding bHLH transcription factor that integrates multiple signaling pathways to regulate cell elongation and plant development. May have a regulatory role in various aspects of gibberellin-dependent growth and development. Interacts with IBH1. Plants over-expressing PRE5 show long hypocotyls, pale green and slightly narrow leaves, elongated petioles and early flowering. They are not sensitive to the gibberellin inhibitor paclobutrazol during seed germination (PubMed:16527868). Belongs to the bHLH protein family.