An investigation into the physiological expression and function of mitochondrial uncoupling protein 1 in thymus

Abstract

Our study confirms the presence of mitochondrial uncoupling protein 1 in thymus. Using laser scanning confocal microscopy, we showed the constitutive expression of UCP 1 in pure thymocytes. Using a primary peptide antibody specific to UCP 1, and secondary fluorescently labelled antibody, we were able to demonstrate that UCP 1 is associated with mitochondria in thymoctes from wild-type mice but not thymocytes from UCP 1 knock-out mice. We are the first lab to demonstrate UCP 1 expression in cells other than brown adipocytes. We also show UCP 1 in thymocytes isolated from rat. As there was data refuting the existence of UCP 1 in thymus/thymocytes, we addressed discrepancies in these studies. We demonstrate that the antibody raised to full length UCP 1 protein appears to be non-specific to UCP 1, as it detects protein in wild-type and UCP 1 knock-out mice thymocyte mitochondria. We also show that CIDEA, a soluble protein with a suggested role in regulating UCP 1 function, is equally abundant in thymocytes from wild-type and UCP 1 knock-out mice. The absence of UCP 1 does not effect native expression of CIDEA in thymocytes. Our study also shows the novel finding that UCP 1 in the thymus has a shorter half-life than UCP 1 in brown adipose tissue mitochondria.