Transcriptional coactivator for CREB1 which activates transcription through both consensus and variant cAMP response element (CRE sites. Acts as a coactivator, in the SIK/TORC signaling pathway, being active when dephosphorylated and acts independently of CREB1 'Ser-133' phosphorylation. Enhances the interaction of CREB1 with TAF4. Regulates the expression of specific CREB-activated genes such as the steroidogenic gene, StAR. Potent coactivator of PGC1alpha and inducer of mitochondrial biogenesis in muscle cells. In the hippocampus, involved in late-phase long-term potentiation (L-LTP maintenance at the Schaffer collateral-CA1 synapses. May be required for dendritic growth of developing cortical neurons (By similarity. In concert with SIK1, regulates the light-induced entrainment of the circadian clock. In response to light stimulus, coactivates the CREB-mediated transcription of PER1 which plays an important role in the photic entrainment of the circadian clock.,CRTC1,MECT1,TORC-1,TORC1,WAMTP1,Epigenetics & Nuclear Signaling,Signal Transduction,Endocrine & Metabolism,Mitochondrial metabolism,Mitochondrial Biogenesis,CRTC1