title: A complex interaction pattern of CIS and SOCS2 with the leptin receptor.
abstract: Hypothalamic leptin receptor signalling plays a central role in weight regulation by controlling fat storage and energy expenditure. In addition, leptin also has direct effects on peripheral cell types involved in regulation of diverse body functions including immune response, bone formation and reproduction. Previous studies have demonstrated the important role of SOCS3 (suppressor of cytokine signalling 3) in leptin physiology. Here, we show that CIS (cytokine-inducible SH2 protein) and SOCS2 can also interact with the leptin receptor. Using MAPPIT (mammalian protein-protein interaction trap), a cytokine receptor-based two-hybrid method operating in intact cells, we show specific binding of CIS with the conserved Y985 and Y1077 motifs in the cytosolic domain of the leptin receptor. SOCS2 only interacts with the Y1077 motif, but with higher binding affinity and can interfere with CIS and STAT5a prey recruitment at this site. Furthermore, although SOCS2 does not associate with Y985 of the leptin receptor, we find that SOCS2 can block interaction of CIS with this position. This unexpected interference can be explained by the direct binding of SOCS2 on the CIS SOCS box, whereby elongin B/C recruitment is crucial to suppress CIS activity.
authors: Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Flanders Interuniversity Institute for Biotechnology, VIB09, Ghent University, Belgium.
authors: Delphine
authors: D
authors: Lavens
authors: Tony
authors: T
authors: Montoye
authors: Julie
authors: J
authors: Piessevaux
authors: Lennart
authors: L
authors: Zabeau
authors: Joël
authors: J
authors: Vandekerckhove
authors: Kris
authors: K
authors: Gevaert
authors: Walter
authors: W
authors: Becker
authors: Sven
authors: S
authors: Eyckerman
authors: Jan
authors: J
authors: Tavernier