2025 Volume 69 Issue 1 Pages 1-7
In mammals, circadian clocks are present in a variety of tissues and cells, and these clocks are classified as the central clock and peripheral clocks. Peripheral clocks are present in various tissues, such as heart, liver and kidney, and are mainly reset by feeding timing and various hormones. However, the synchronization mechanisms of individual peripheral clocks via hormones and their receptors remain unclear. In our previous studies, Multi-PK antibodies (M1C, M8C and YK34) which directed to a highly conserved region of protein kinases were developed. M1C and M8C antibodies recognize a wide variety of serine/threonine protein kinases and YK34 antibody detects tyrosine protein kinases. In this study, we analyzed diurnal variation of tyrosine kinases in cell membrane fractions from mouse peripheral tissues by Western blotting using YK34 antibody. Diurnal variation of tyrosine kinase expression was detected in heart, liver, and kidney. In the liver, the 180-kDa and 130-kDa bands that changed diurnally were identified as epidermal growth factor receptor (EGFR). EGFR was not expressed in other peripheral tissues. These results suggest that EGFR may contribute to the synchronization of the circadian clock in mouse liver.
