UCP1 and obesity due to melanocortin 4 receptor deficiency: However, it is a distinct possibility that the blunted development of obesity in these studies with no detectable induction of UCP1 expression in BRITE or brown adipocytes may be caused by UCP1-independent mechanisms including creatine-driven cycles and/or SERCA2b-dependent Ca2+ cycling, and future studies on the possible involvement of such mechanisms in response to intake of high protein diets would clearly be of interest.