Human ClC-6 Is a Late Endosomal Glycoprotein that Associates with Detergent-Resistant Lipid Domains

BACKGROUND: The mammalian CLC protein family comprises nine members (ClC-1 to -7 and ClC-Ka, -Kb) that function either as plasma membrane chloride channels or as intracellular chloride/proton antiporters, and that sustain a broad spectrum of cellular processes, such as membrane excitability, transepithelial transport, endocytosis and lysosomal degradation. In this study we focus on human ClC-6, which is structurally most related to the late endosomal/lysomal ClC-7. PRINCIPAL FINDINGS: Using a polyclonal affinity-purified antibody directed against a unique epitope in the ClC-6 COOH-terminal tail, we show that human ClC-6, when transfected in COS-1 cells, is N-glycosylated in a region that is evolutionary poorly conserved between mammalian CLC proteins and that is located between the predicted helices K and M. Three asparagine residues (N410, N422 and N432) have been defined by mutagenesis as acceptor sites for N-glycosylation, but only two of the three sites seem to be simultaneously N-glycosylated. In a differentiated human neuroblastoma cell line (SH-SY5Y), endogenous ClC-6 colocalizes with LAMP-1, a late endosomal/lysosomal marker, but not with early/recycling endosomal markers such as EEA-1 and transferrin receptor. In contrast, when transiently expressed in COS-1 or HeLa cells, human ClC-6 mainly overlaps with markers for early/recycling endosomes (transferrin receptor, EEA-1, Rab5, Rab4) and not with late endosomal/lysosomal markers (LAMP-1, Rab7). Analogously, overexpression of human ClC-6 in SH-SY5Y cells also leads to an early/recycling endosomal localization of the exogenously expressed ClC-6 protein. Finally, in transiently transfected COS-1 cells, ClC-6 copurifies with detergent-resistant membrane fractions, suggesting its partitioning in lipid rafts. Mutating a juxtamembrane string of basic amino acids (amino acids 71-75: KKGRR) disturbs the association with detergent-resistant membrane fractions and also affects the segregation of ClC-6 and ClC-7 when cotransfected in COS-1 cells. CONCLUSIONS: We conclude that human ClC-6 is an endosomal glycoprotein that partitions in detergent resistant lipid domains. The differential sorting of endogenous (late endosomal) versus overexpressed (early and recycling endosomal) ClC-6 is reminiscent of that of other late endosomal/lysosomal membrane proteins (e.g. LIMP II), and is consistent with a rate-limiting sorting step for ClC-6 between early endosomes and its final destination in late endosomes

Resolution of inflammation: a new therapeutic frontier

Dysregulated inflammation is a central pathological process in diverse disease states. Traditionally, therapeutic approaches have sought to modulate the pro- or anti-inflammatory limbs of inflammation, with mixed success. However, insight into the pathways by which inflammation is resolved has highlighted novel opportunities to pharmacologically manipulate these processes — a strategy that might represent a complementary (and perhaps even superior) therapeutic approach. This Review discusses the state of the art in the biology of resolution of inflammation, highlighting the opportunities and challenges for translational research in this field

DDInnere as interactive ebook package for internal medicine featuring diagnoses, symptoms and laboratory values

DDInnere is a symptom-based compendium of internal medicine and consists of three separate ebooks for diagnoses, symptoms and laboratory values for handheld computers and smartphones. Our programs aim to provide medical knowledge at the point of care. This is also achieved by use of the well established Mobipocket Reader, which is the runtime environment not only for our programs but as well for medical ebooks from other providers (http://www.mobipocket.de). Future aims include a more detailed understanding of the role of these applications in medical care and an even better integration of our solutions into clinical processes.Die DDInnere als leitsymptombasiertes Kompendium der Inneren Medizin besteht aus separaten Ebooks für Diagnosen, Leitsymptome und Laborwerte für Handcomputer und Smartphones. Das Ziel unserer Programme ist es, medizinisches Wissen schnell und aktuell direkt im Klinikalltag, in der Praxis und am Krankenbett verfügbar zu machen. Dazu dient auch die Nutzung des weitverbreiteten Mobipocket Readers, über den unsere Programme wie auch die Medizin-Ebooks anderer Anbieter genutzt werden können (http://www.mobipocket.de). Für die Zukunft möchten wir nun die Rolle dieser Wissensvermittler in der praktischen Medizin genauer verstehen, um unsere Lösungen damit noch besser in die klinischen Abläufe zu integrieren