The GTPase activating factor for transducin in rod photoreceptors is the complex between RGS9 and type 5 G protein β subunit

Proteins of the regulators of G protein signaling (RGS) family modulate the duration of intracellular signaling by stimulating the GTPase activity of G protein α subunits. It has been established that the ninth member of the RGS family (RGS9) participates in accelerating the GTPase activity of the photoreceptor-specific G protein, transducin. This process is essential for timely inactivation of the phototransduction cascade during the recovery from a photoresponse. Here we report that functionally active RGS9 from vertebrate photoreceptors exists as a tight complex with the long splice variant of the G protein β subunit (Gβ5L). RGS9 and Gβ5L also form a complex when coexpressed in cell culture. Our data are consistent with the recent observation that several RGS proteins, including RGS9, contain G protein γ-subunit like domain that can mediate their association with Gβ5 (Snow, B. E., Krumins, A. M., Brothers, G. M., Lee, S. F., Wall, M. A., Chung, S., Mangion, J., Arya, S., Gilman, A. G. & Siderovski, D. P. (1998) Proc. Natl. Acad. Sci. USA 95, 13307–13312). We report an example of such a complex whose cellular localization and function are clearly defined.

Dissecting the role of the Golgi complex and lipid rafts in biosynthetic transport of cholesterol to the cell surface

In this study, we compared the transport of newly synthesized cholesterol with that of influenza virus hemagglutinin (HA) from the endoplasmic reticulum to the plasma membrane. The arrival of cholesterol on the cell surface was monitored by cyclodextrin removal, and HA transport was monitored by surface trypsinization and endoglycosidase H digestion. We found that disassembly of the Golgi complex by brefeldin A treatment resulted in partial inhibition of cholesterol transport while completely blocking HA transport. Further, microtubule depolymerization by nocodazole inhibited cholesterol and HA transport to a similar extent. When the partitioning of cholesterol into lipid rafts was analyzed, we found that newly synthesized cholesterol began to associate with low-density detergent-resistant membranes rapidly after synthesis, before it was detectable on the cell surface, and its raft association increased further upon chasing. When cholesterol transport was blocked by using 15°C incubation, the association of newly synthesized cholesterol with low-density detergent-insoluble membranes was decreased and cholesterol accumulated in a fraction with intermediate density. Our results provide evidence for the partial contribution of the Golgi complex to the transport of newly synthesized cholesterol to the cell surface and suggest that detergent-resistant membranes are involved in the process.

Towards Better Use of Credit Reporting in Europe. CEPS-ECRI Task Force Report, September 2013

This report discusses how the current EU credit reporting systems meet the demands of the different stakeholders in the credit granting and management process, and what is needed to improve these systems. As credit reporting is a tool for responsible lending and for ensuring financial inclusion of consumers, it argues that the needs of EU credit markets and consumers should be the basis for assessing the current regulation and its functionality. How a creditor assesses the risk and the creditworthiness of a customer is at the core of successful and safe crediting. Facilitating this assessment process, within the boundaries of data protection laws, is a key building block for making well-informed credit decisions.

The Impact of Spain’s Economic and Political Crisis on the European Elections. EPIN Commentaries No. 17, 2 April 2014

Despite the emergence of a critical debate against the EU-imposed austerity measures both at the level of the political elites and on the street, this EPIN Commentary by two Spanish political scientists based in Barcelona finds no sign that the upcoming European elections will have a more European focus than any of the previous ones. While there is no anti-European discourse among the Spanish mainstream political parties, they report that public trust in the European institutions is plummeting and Spanish turnout in European elections has been dropping in the last few years. In the authors’ view, the main reason for this is the low level of awareness of the functioning of the European Parliament but some responsibility also lies with the Spanish political parties and the way they deal with the electoral campaign to mobilise the discontented voters, who consider unemployment and the economic situation as the two most important issues that the country is facing at the moment.