Z5 - Molecular mechanisms of action of adipokines
Adipokines are released from adipose tissue and influence the metabolism of the whole organism. Accordingly, increased body fat leads to an increased or reduced release of adipokines dependent on their regulation which can subsequently explain dysfunctions in obesity. Several adipokines have been correlated with obesity, including adiponectin, vaspin, Dlk1/Pref-1 (delta-like homolog 1; preadipocyte factor 1) and chemerin. However, so far little is known about their molecular mechanism of function. We successfully cloned and expressed full-length and globular adiponectin, vaspin, Dlk1/Pref-1, prochemerin and chemerin. These adipokines have been identified by genetic studies or expression analysis of visceral and subcutaneous fat. The aim of the project is now to identify their targets, to find novel interacting partners and elucidate the molecular mechanisms of their physiological activity. We hypothesize that site specific and selectively labeled adipokines will provide novel target molecules of interaction and allow elucidating adipokine function and their roles in adipositas. In the first period of the project we will include adiponectin, vaspin, DLK1/Pref-1 and chemerin, which have been shown to play an important role in obesity and its related metabolic diseases. Proteins will be expressed recombinantly for structural analysis, and chemically modified in order to perform localization studies and identify interaction partners by co-immunoprecipitation. On the one hand, adipokines will be fluorescently labeled to follow their distribution, binding on cells and to perform in vitro assays. On the other hand, addition of biotin labels will allow co-immunoprecipitation of adipokines from cell culture supernatant or blood and modification with chelators the production of gadolinium-labeled adipokines for MRT-distribution studies in living mice. The obtained information will answer the question on the role of these important adipokines and their interplay with respect to obesity.
Figure 1. Expression and characterization of vaspin, full length and globular adiponectin, and crystal structure of vaspin as publishedin Heiker J et al. Cell Mol Life Sci (2013).
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