Search results for "Subunit"
showing 10 items of 513 documents
Two α subunits and one β subunit of meprin zinc-endopeptidases are differentially expressed in the zebrafish Danio rerio
2007
Abstract Meprins are members of the astacin family of metalloproteases expressed in epithelial tissues, intestinal leukocytes and certain cancer cells. In mammals, there are two homologous subunits, which form complex glycosylated disulfide-bonded homo- and heterooligomers. Both human meprin α and meprin β cleave several basement membrane components, suggesting a role in epithelial differentiation and cell migration. There is also evidence that meprin β is involved in immune defence owing to its capability of activating interleukin-1β and the diminished mobility of intestinal leukocytes in meprin β-knockout mice. Here we show for the first time by reverse transcription PCR, immunoblotting a…
Mapping of a binding site for ATP within the extracellular region of the Torpedo nicotinic acetylcholine receptor beta-subunit.
1997
Using 2,8,5'-[H-3]ATP as a direct photoaffinity label for membrane-bound nicotinic acetylcholine receptor (nAChR) from Torpedo marmorata, we have identified a binding site for ATP in the extracellular region of the beta-subunit of the receptor. Photolabeling was completely inhibited in the presence of saturating concentrations of nonradioactive ATP, whereas neither the purinoreceptor antagonists suramin, theophyllin, and caffeine nor the nAChR antagonists alpha-bungarotoxin and d-tubocurarine affected the labeling reaction. Competitive and noncompetitive nicotinic agonists and Ca2+ increased the yield of the photoreaction by up to 50%, suggesting that the respective binding sites are allost…
Complete Sequence of the 24-mer Hemocyanin of the TarantulaEurypelma californicum
2000
Hemocyanins are large oligomeric respiratory proteins found in many arthropods and molluscs. The hemocyanin of the tarantula Eurypelma californicum is a 24-mer protein complex with molecular mass of 1,726,459 Da that consists of seven different polypeptides (a–g), each occupying a distinct position within the native molecule. Here we report the complete molecular structure of the E. californicumhemocyanin as deduced from the corresponding cDNAs. This represents the first complex arthropod hemocyanin to be completely sequenced. The different subunits display 52–66% amino acid sequence identity. Within the subunits, the central domain, which bears the active center with the copper-binding sit…
9 Å cryo-EM structure and molecular model of a gastropod hemocyanin didecamer (KLH1) reveals the architecture of the asymmetric collar
2008
Hemocyanins are blue copper proteins that transport oxygen in the hemolymph of many arthropods and molluscs. Molluscan hemocyanins are decamers, didecamers or multidecamers of a 350–400 kDa polypeptide subunit that is subdivided into seven or eight different functional units (FUs, each with a single copper active site). The quaternary structure is a semi-hollow cylinder consisting of a wall and a collar. Recently, we published a 9 A cryo-EM structure and molecular model of a cephalopod hemocyanin decamer (NpH, from Nautilus pompilius) that answered many hitherto unsolved questions concerning the quaternary structure of molluscan hemocyanin. Notably, it revealed the twisted pathway of the 10…
IL12A, MPHOSPH9/CDK2AP1 and RGS1 are novel multiple sclerosis susceptibility loci
2010
A recent meta-analysis identified seven single-nucleotide polymorphisms (SNPs) with suggestive evidence of association with multiple sclerosis (MS). We report an analysis of these polymorphisms in a replication study that includes 8,085 cases and 7,777 controls. A meta-analysis across the replication collections and a joint analysis with the discovery data set were performed. The possible functional consequences of the validated susceptibility loci were explored using RNA expression data. For all of the tested SNPs, the effect observed in the replication phase involved the same allele and the same direction of effect observed in the discovery phase. Three loci exceeded genome-wide significa…
A Novel CCT5 Missense Variant Associated with Early Onset Motor Neuropathy
2020
Diseases associated with acquired or genetic defects in members of the chaperoning system (CS) are increasingly found and have been collectively termed chaperonopathies. Illustrative instances of genetic chaperonopathies involve the genes for chaperonins of Groups I (e.g., Heat shock protein 60, Hsp60) and II (e.g., Chaperonin Containing T-Complex polypeptide 1, CCT). Examples of the former are hypomyelinating leukodystrophy 4 (HLD4 or MitCHAP60) and hereditary spastic paraplegia (SPG13). A distal sensory mutilating neuropathy has been linked to a mutation [p.(His147Arg)] in subunit 5 of the CCT5 gene. Here, we describe a new possibly pathogenic variant [p.(Leu224Val)] of the same subunit b…
Increased immunosuppressive function of CD4(+)CD25(+)Foxp3(+)GITR+ T regulatory cells from NFATc2((-/-)) mice controls allergen-induced experimental …
2012
The expansion of effector T cells is tightly controlled by transcription factors like nuclear factor of activated T cells (NFAT) family members that mediate early intracellular responses to T cell receptor-mediated signals. In this study we show that, after allergen challenge, NFATc2((-/-)) mice had augmented number of functionally intact CD4(+)CD25(++)GITR(++) T regulatory (T regs) cells in the lung. Anti-GITR antibody treatment inhibited T regulatory cell function and enhanced the number of activated lung CD4(+) T cells associated with increased IL-2 and pSTAT-5 in the airways of NFATc2((-/-)) mice in experimental allergic asthma. This agonistic treatment led to increased inflammation in …
The Role of Erythropoietin in Neuroprotection: Therapeutic Perspectives
2007
Nervous system diseases are very complex conditions comprising a large variety of local and systemic responses. Several therapeutic agents interfering with all or in part the biochemical steps that ultimately cause neuronal death have been demonstrated to be neuroprotective in preclinical models. However, all the agents so far investigated have inexorably failed in the phase III trials carried out. A large body of evidence suggests that the hormone erythropoietin (EPO), besides its well-known hematopoietic action, exerts beneficial effects in the central nervous system. EPO's effect has been assessed in several experimental models of brain and spinal cord injury thus becoming a serious cand…
Neuronal Nicotinic Receptors in the Locust Locusta migratoria
1998
We have identified five cDNA clones that encode nicotinic acetylcholine receptor (nAChR) subunits expressed in the nervous system of the locust Locusta migratoria. Four of the subunits are ligand-binding α subunits, and the other is a structural β subunit. The existence of at least one more nAChR gene, probably encoding a β subunit, is indicated. Based on Northern analysis and in situ hybridization, the five subunit genes are expressed. locα1, locα3, andlocβ1 are the most abundant subunits and are expressed in similar areas of the head ganglia and retina of the adult locust. Because Locα3 binds α-bungarotoxin with high affinity, it may form a homomeric nAChR subtype such as the mammalian α7…
NG2-expressing cells in the nervous system revealed by the NG2-EYFP-knockin mouse.
2008
The NG2 glycoprotein is a type I membrane protein expressed by immature cells in the developing and adult mouse. NG2+ cells of the embryonic and adult brain have been principally viewed as oligodendrocyte precursor cells but have additionally been considered a fourth glial class. They are likely to be a heterogeneous population. In order to facilitate studies on the function of NG2+ cells and to characterize these cells in situ, we generated an enhanced yellow fluorescent protein (EYFP) “knockin mouse.” EYFP-expressing cells in heterozygous knockin mice expressed the NG2 protein in all regions and at all ages studied. The EYFP+ cells did not express markers of mature glia, developing or mat…