cAMP response element-binding protein-regulated transcription co-activator 1 (CRTC1)

cAMP response element-binding protein-regulated transcription co-activator 1 (CRTC1) is a key transcriptional co-activator that mediates cellular responses to cAMP and calcium signaling by enhancing the activity of the CREB transcription factor [1, 3]. Under basal conditions, CRTC1 is phosphorylated by Salt-inducible kinases (SIKs) and sequestered in the cytoplasm; upon activation, it is dephosphorylated by calcineurin and translocates to the nucleus to bind CREB and promote the expression of genes involved in metabolism, memory, and circadian rhythms [1, 7, 12]. In clinical oncology, CRTC1 is most prominent as a fusion partner, where the CRTC1-MAML2 translocation acts as the primary driver for mucoepidermoid carcinoma, a common salivary gland malignancy [13, 15]. Additionally, novel fusions like CRTC1-TRIM11 have been identified as drivers in specific cutaneous melanocytic tumors [17, 18]. Beyond cancer, CRTC1 dysregulation is implicated in neurodegenerative conditions like Alzheimer's disease and metabolic disorders like obesity [6, 10]. While direct pharmacological inhibition of CRTC1 remains a therapeutic challenge, experimental small molecules like 666-15 target its interaction with CREB, and indirect modulation is explored via SIK inhibitors or downstream targeting of CRTC1 fusion signaling pathways [13, 16].

Other names

CREB-regulated transcription coactivator 1Transducer of regulated cAMP response element-binding protein 1TORC1MECT1WAMTP1Mucoepidermoid carcinoma translocated protein 1

CRTC1 acts as a co-activator by binding to the basic leucine zipper (bZIP) domain of the transcription factor CREB (cAMP response element-binding protein), thereby enhancing its ability to recruit the transcriptional machinery (such as TAF4 and CBP/p300) to cAMP-responsive elements (CRE) in target gene promoters [1, 3, 7]. Its activity is regulated by its subcellular localization: phosphorylation by Salt-inducible kinases (SIK) leads to cytoplasmic sequestration by 14-3-3 proteins, while dephosphorylation by calcineurin triggers nuclear translocation and activation [1, 3, 12].