The long coiled-coil protein NECC2 is associated to caveolae and modulates NGF/TrkA signaling in PC12 cells [corrected].

TrkA-mediated NGF signaling in PC12 cells has been shown to be compartimentalized in specialized microdomains of the plasma membrane, the caveolae, which are organized by scaffold proteins including the member of the caveolin family of proteins, caveolin-1. Here, we characterize the intracellular distribution as well as the biochemical and functional properties of the neuroendocrine long coiled-coil protein 2 (NECC2), a novel long coiled-coil protein selectively expressed in neuroendocrine tissues that contains a predicted caveolin-binding domain and displays structural characteristics of a scaffolding factor. NECC2 distributes in caveolae, wherein it colocalizes with the TrkA receptor, and behaves as a caveolae-associated protein in neuroendocrine PC12 cells. In addition, stimulation of PC12 cells with nerve growth factor (NGF) increased the expression and regulated the distribution of NECC2. Interestingly, knockdown as well as overexpression of NECC2 resulted in a reduction of NGF-induced phosphorylation of the TrkA downstream effector extracellular signal-regulated kinases 1 and 2 (ERK1/ERK2) but not of Akt. Altogether, our results identify NECC2 as a novel component of caveolae in PC12 cells and support the contribution of this protein in the maintenance of TrkA-mediated NGF signaling.journal articleresearch support, non-u.s. gov't20132013 09 06importe

The caveolae-associated coiled-coil protein, NECC2, regulates insulin signalling in Adipocytes

Adipocyte dysfunction in obesity is commonly associated with impaired insulin sig-nalling in adipocytes and insulin resistance. Insulin signalling has been associatedwith caveolae, which are coated by large complexes of caveolin and cavin proteins,along with proteins with membrane‐binding and remodelling properties. Here, weanalysed the regulation and function of a component of caveolae involved in growthfactor signalling in neuroendocrine cells, neuroendocrine long coiled‐coil protein‐2(NECC2), in adipocytes. Studies in 3T3‐L1 cells showed that NECC2 expressionincreased during adipogenesis. Furthermore, NECC2 co‐immunoprecipitated withcaveolin‐1 (CAV1) and exhibited a distribution pattern similar to that of the compo-nents of adipocyte caveolae, CAV1, Cavin1, the insulin receptor and cortical actin.Interestingly, NECC2 overexpression enhanced insulin‐activated Akt phosphoryla-tion, whereas NECC2 downregulation impaired insulin‐induced phosphorylation ofAkt and ERK2. Finally, an up‐regulation ofNECC2in subcutaneous and omental adi-pose tissue was found in association with human obesity and insulin resistance. Thiseffect was also observed in 3T3‐L1 adipocytes exposed to hyperglycaemia/hyperin-sulinemia. Overall, the present study identifies NECC2 as a component of adipocytecaveolae that is regulated in response to obesity and associated metabolic complica-tions, and supports the contribution of this protein as a molecular scaffold modulat-ing insulin signal transduction at these membrane microdomains

The caveolae-associated coiled-coil protein, NECC2, regulates insulin signalling in Adipocytes

Adipocyte dysfunction in obesity is commonly associated with impaired insulin sig-nalling in adipocytes and insulin resistance. Insulin signalling has been associatedwith caveolae, which are coated by large complexes of caveolin and cavin proteins,along with proteins with membrane‐binding and remodelling properties. Here, weanalysed the regulation and function of a component of caveolae involved in growthfactor signalling in neuroendocrine cells, neuroendocrine long coiled‐coil protein‐2(NECC2), in adipocytes. Studies in 3T3‐L1 cells showed that NECC2 expressionincreased during adipogenesis. Furthermore, NECC2 co‐immunoprecipitated withcaveolin‐1 (CAV1) and exhibited a distribution pattern similar to that of the compo-nents of adipocyte caveolae, CAV1, Cavin1, the insulin receptor and cortical actin.Interestingly, NECC2 overexpression enhanced insulin‐activated Akt phosphoryla-tion, whereas NECC2 downregulation impaired insulin‐induced phosphorylation ofAkt and ERK2. Finally, an up‐regulation ofNECC2in subcutaneous and omental adi-pose tissue was found in association with human obesity and insulin resistance. Thiseffect was also observed in 3T3‐L1 adipocytes exposed to hyperglycaemia/hyperin-sulinemia. Overall, the present study identifies NECC2 as a component of adipocytecaveolae that is regulated in response to obesity and associated metabolic complica-tions, and supports the contribution of this protein as a molecular scaffold modulat-ing insulin signal transduction at these membrane microdomains