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Tight junctions seal the paracellular pathway of epithelia but, in leaky tissues, also exhibit specific permeability. In order to characterize the contribution of claudin-2 to barrier and permeability properties of the tight junction in detail, we studied two strains of Madin-Darby canine kidney cells (MDCK-C7 and MDCK-C11) with different tight junctional(More)
The A2a adenosine receptor is a member of the G-protein coupled receptor family, and its activation stimulates cyclic AMP production. To determine the residues which are involved in ligand binding, several residues in transmembrane domains 5-7 were individually replaced with alanine and other amino acids. The binding properties of the resultant mutant(More)
To test the hypothesis that G protein-coupled receptors consist of multiple autonomous folding domains, the rat m3 muscarinic acetylcholine receptor was "split" in all three intracellular (i1-i3) and all three extracellular loops (o2-o4). The six resulting polypeptide pairs (Ni1.Ci1, No2.Co2, etc.) were coexpressed in COS-7 cells and studied for their(More)
Gain-of-function mutations of the thyrotropin receptor (TSHR) gene have been invoked as one of the major causes of toxic thyroid adenomas. In a toxic thyroid nodule, we recently identified a 9-amino acid deletion (amino acid positions 613-621) within the third intracellular (i3) loop of the TSHR resulting in constitutive receptor activity. This finding(More)
Hyperfunctional endocrine thyroid and testicular disorders can frequently be traced back to gainof-function mutations in glycoprotein hormone receptor genes. Deletion mutations in the third intracellular (i3) loop of the TSH receptor have recently been identified as a cause of constitutive receptor activity. To examine whether the underlying mechanism of(More)
Genetic variation in Avpr1a, the locus encoding the arginine vasopressin receptor 1A (V1aR), has been implicated in pair-bonding behavior in voles (genus Microtus) and humans, raising the possibility that this gene may contribute commonly to mating-system variation in mammals. In voles, differential expression of V1aR in the brain is associated with male(More)
A prerequisite for the maintenance of homeostasis in a living organism is fine-tuned communication between different cells. The majority of extracellular signaling molecules, such as hormones and neurotransmitters, interact with a three-protein transmembrane signaling system consisting of a receptor, a G protein, and an effector. These single components(More)
The nuclear envelope (NE) is one of the least characterized structures of eukaryotic cells. The study of its functional roles is hampered by the small number of proteins known to be specifically located to it. Here, we present a comprehensive characterization of the NE proteome. We applied different fractionation procedures and isolated protein subsets(More)
Intense neuronal activity in the sensory retina is associated with a volume increase of neuronal cells (Uckermann et al., J. Neurosci. 2004, 24:10149) and a decrease in the osmolarity of the extracellular space fluid (Dmitriev et al., Vis. Neurosci. 1999, 16:1157). Here, we show the existence of an endogenous purinergic mechanism that prevents hypoosmotic(More)
Interaction and cross-talk of G-protein-coupled receptors (GPCRs) are of considerable interest because an increasing number of examples implicate a profound functional and physiological relevance of homo- or hetero-oligomeric GPCRs. The ghrelin (growth hormone secretagogue receptor (GHSR)) and melanocortin-3 (MC3R) receptors are both known to have(More)