6. Summary and perspectives
Although the interplay of excessive food intake, physical inactivity,and genetic susceptibility underlies most cases of obesity, the signals and mechanisms that trigger fat accumulation by disrupting energy homeostasis are not well understood. The startling rise in the number of people who are obese, together with the inability of most individuals
to comply with treatment regimens that require sustained lifestyle changes, has stimulated efforts to identify new therapeutic targets for the treatment and prevention of this pervasive disorder. One potential new target is protein kinase C beta. In this review, we describe different aspects of protein kinase C beta activation and adipose dysfunction and propose a mechanism for how these aspects may be inter-related and might play a crucial role in the pathogenesis of obesity and related metabolic abnormalities.Emerging evidence suggests that disruption of the protein kinase C beta/p66shc/mitochondrial axis leads to disturbances in adipose mitochondrial dysfunction, adipocyte hypertrophy, oxidative stress, and inflammation within the adipose tissue, which may result in obesity and insulin resistance. protein kinase C beta repression appears to be an important component of the beneficial metabolic response to exercise. The above data led us to hypothesize that protein kinase C beta is part of the body's program to conserve all extra calories as fat against a time when calories might be scarce, but in the current prevailing situation of overeating and a sedentary lifestyle the enzyme actually provides a survival disadvantage. The above studies have clearly advanced our understanding of the role of protein kinase C beta in energy homeostasis; however, there are still many unanswered questions concerning the precise cascade of events that link protein kinase C beta activation with the development and progression of adipose tissue dysfunction. Large-scale prospective human studies are also required to confirm the data from animal models and establish protein kinase C beta as a potential therapeutic target for the treatment of obesity and related syndromes.