SIK1 and schizophrenia: Since it was previously reported that CRTC1 is expressed almost exclusively in the hypothalamus and CRTC3 is expressed in adipose tissue (Altarejos and Montminy, 2011), the SIK1/CRTC2/CREB1 signaling pathway was selected and its involvement in the pathophysiology of schizophrenia was investigated in this study.