Performance of a SARS CoV-2 antibody ELISA based on simultaneous measurement of antibodies against the viral nucleoprotein and receptor-binding domain.

SARS CoV-2 antibody assays measure antibodies against the viral nucleoprotein (NP) or spike protein. The study examined if testing of antibodies against both antigens increases the diagnostic sensitivity. Sera (N=98) from infected individuals were tested with ELISAs based on the NP, receptor-binding domain (RBD), or both proteins.

The Multitarget Ligand 3-Iodothyronamine Modulates β-Adrenergic Receptor 2 Signaling.

Background: 3-Iodothyronamine (3-T1AM), a signaling molecule with structural similarities to thyroid hormones, induces numerous physiological responses including reversible body temperature decline. One target of 3-T1AM is the trace amine-associated receptor 1 (TAAR1), which is a member of the rhodopsin-like family of G protein-coupled receptors (GPCRs). Interestingly, the effects of 3-T1AM remain detectable in TAAR1 knockout mice, suggesting further targets for 3-T1AM such as adrenergic receptors.

Identification of determinants required for agonistic and inverse agonistic ligand properties at the ADP receptor P2Y12.

The ADP receptor P2Y(12) belongs to the superfamily of G protein-coupled receptors (GPCRs), and its activation triggers platelet aggregation. Therefore, potent antagonists, such as clopidogrel, are of high clinical relevance in prophylaxis and treatment of thromboembolic events. P2Y(12) displays an elevated basal activity in vitro, and as such, inverse agonists may be therapeutically beneficial compared with antagonists.

The ligand specificity of the G-protein-coupled receptor GPR34.

Lyso-PS (lyso-phosphatidylserine) has been shown to activate the G(i/o)-protein-coupled receptor GPR34. Since in vitro and in vivo studies provided controversial results in assigning lyso-PS as the endogenous agonist for GPR34, we investigated the evolutionary conservation of agonist specificity in more detail. Except for some fish GPR34 subtypes, lyso-PS has no or very weak agonistic activity at most vertebrate GPR34 orthologues investigated.

Characterization of the expression, promoter activity and molecular architecture of fibin.

Background: Fibin was initially discovered as a secreted signal molecule essential for pectoral fin bud initiation in zebrafish. Currently, there is little information about the molecular architecture and biological relevance of fibin in humans and other mammals.

Results: Fibin is expressed in cerebellum, skeletal muscle and many other embryonic and adult mouse tissues suggesting not only a role during embryonic development but also in adult functions.

Involvement of the V2 vasopressin receptor in adaptation to limited water supply.

Mammals adapted to a great variety of habitats with different accessibility to water. In addition to changes in kidney morphology, e.g.

KIT variants in bovine ovarian cells and corpus luteum.

We report the presence of KIT variants in granulosa and thecal cells of the follicle and endothelial and steroidogenic cells of the corpus luteum. Transcripts of both full-length splice variants, KIT and KITA, were ubiquitously detected in all cell types, in contrast to transcripts for truncated KIT. RT-PCR with exon-intron-specific primers suggested that KIT transcripts retained intron sequences.

Structural and functional evolution of the P2Y(12)-like receptor group.

Metabotropic pyrimidine and purine nucleotide receptors (P2Y receptors) belong to the superfamily of G protein-coupled receptors (GPCR). They are distinguishable from adenosine receptors (P1) as they bind adenine and/or uracil nucleotide triphosphates or diphosphates depending on the subtype. Over the past decade, P2Y receptors have been cloned from a variety of tissues and species, and as many as eight functional subtypes have been characterized.

Generation of an agonistic binding site for blockers of the M(3) muscarinic acetylcholine receptor.

GPCRs (G-protein-coupled receptors) exist in a spontaneous equilibrium between active and inactive conformations that are stabilized by agonists and inverse agonists respectively. Because ligand binding of agonists and inverse agonists often occurs in a competitive manner, one can assume an overlap between both binding sites. Only a few studies report mutations in GPCRs that convert receptor blockers into agonists by unknown mechanisms.

Molecular basis and clinical features of nephrogenic diabetes insipidus.

Maintenance of water and electrolyte homeostasis is central to mammalian survival and, therefore, under stringent hormonal control. Water homeostasis is achieved by balancing fluid intake with water excretion, governed by the antidiuretic action of arginine vasopressin. Arginine vasopressin stimulation of renal V vasopressin receptors in the basolateral membrane of principal cells induces aquaporin-2-mediated water reabsorption in the kidney.

Renaturation of the catalytic domain of PDE4A expressed in Escherichia coli as inclusion bodies.

Owing to simplicity, speed, cost advantage, and a generally high product yield, expression in Escherichia coli is the method of choice for the production of large amounts of protein. However, because of the high expression level, proteins often accumulate within the cells as insoluble aggregates called inclusion bodies. The inclusion body protein is misfolded and biologically inactive and, thus, needs to be refolded into its native conformation.

Mutant G-protein-coupled receptors as a cause of human diseases.

G-protein-coupled receptors (GPCR) are involved in directly and indirectly controlling an extraordinary variety of physiological functions. Their key roles in cellular communication have made them the target for more than 60% of all currently prescribed drugs. Mutations in GPCR can cause acquired and inherited diseases such as retinitis pigmentosa (RP), hypo- and hyperthyroidism, nephrogenic diabetes insipidus, several fertility disorders, and even carcinomas.

Detrusor smooth muscle cells of the guinea-pig are functionally coupled via gap junctions in situ and in cell culture.

Intercellular communication between smooth muscle cells is crucial for contractile behaviour in normal and pathologically altered urinary bladder. Since the study of coupling is difficult in situ, we established cell cultures of bladder smooth muscle cells to analyse coupling mechanisms. Microinjection of Lucifer yellow demonstrated syncytia composed of only a few to several dozen cells.

Refolding and purification of recombinant human PDE7A expressed in Escherichia coli as inclusion bodies.

We have investigated the refolding and purification of the catalytic domain of human 3',5'-cyclic nucleotide phosphodiesterase 7A1 (PDE7A1) expressed in Escherichia coli. A cDNA encoding an N-terminal-truncated PDE7A1(147-482-His) was amplified by RT-PCR from human peripheral blood cells and inserted into the vector pET21-C for bacterial expression of the enzyme fused to a C-terminal His-tag. The PDE was found to be expressed in the form of inclusion bodies which could be refolded to an active enzyme in buffer containing high concentrations of arginine hydrochloride, ethylene glycol, and magnesium chloride at pH 8.