Transcription activator (PubMed:14581622). Binds to the DNA consensus sequence 5'-[ACG]CGCG[GTC]-3' (By similarity). Regulates transcriptional activity in response to calcium signals (Probable). Binds calmodulin in a calcium-dependent manner (By similarity). Involved in response to cold. Contributes together with CAMTA3 to the positive regulation of the cold-induced expression of DREB1A/CBF3, DREB1B/CBF1 and DREB1C/CBF2 (PubMed:28351986). Expressed in roots, stems, leaves, pollen, top of sepals and siliques. By heat shock, UVB, wounding, abscisic acid, H(2)O(2) and salicylic acid. Belongs to the CAMTA family.