scholarly journals Chimeric Antibody-Binding Vitreoscilla Hemoglobin (VHb) Mediates Redox-Catalysis Reaction: New Insight into the Functional Role of VHb

2006 ◽  
pp. 208-215 ◽  
Author(s):  
Yaneenart Suwanwong ◽  
Malin Kvist ◽  
Chartchalerm Isarankura-Na-Ayudhya ◽  
Natta Tansila ◽  
Leif Bulow ◽  
...  
Keyword(s):  
Functional Role ◽  
Antibody Binding ◽  
Vitreoscilla Hemoglobin ◽  
Chimeric Antibody ◽  
Redox Catalysis ◽  
Insight Into

Comparative studies on glial markers

1981 ◽  
Vol 95 (1) ◽  
pp. 167-180
Author(s):  
B. I. Roots
Keyword(s):  
Manduca Sexta ◽  
Comparative Studies ◽  
Nervous Tissue ◽  
Functional Role ◽  
Functional Interactions ◽  
Lower Vertebrates ◽  
Fresh Insight ◽  
Insight Into ◽  
Biochemical Differentiation

Macromolecular markers for glial cells have been sought for a variety of reasons. One of the earliest was the need for a means of assessing the purity of cell and subcellular fractions prepared from nervous tissue. While there is still a requirement for this kind of tool, emphasis has shifted towards seeking information on biochemical differentiation among cells and their functional interactions. A brief general review will be made of glial markers and two of these, 2′,3′-cyclic nucleotide 3′-phosphohydrolase (CNP) and glutamine synthetase (GS), will be considered in detail. Until recently studies of markers have been concentrated on the higher vertebrates and those on lower vertebrates and invertebrates have hardly begun. However, such comparative studies may lead to fresh insight into old problems. For example, CNP has long been regarded as a marker for myelin and oligodendrocytes but it has not been possible to attribute a functional role to it and its relation to myelination has remained obscure. The finding that it is present in the glia of a moth Manduca sexta which lacks myelin provides a stimulus for a fresh approach to the problem. Another example is provided by studies on GS. This enzyme is found in astrocyte feet and preliminary results indicate that it is localized also in the perineurial glia of Aplysia ganglia. These results lead to a reconsideration of the perennial question of the possible role of astrocyte feet in barrier mechanisms. Extension of comparative studies may not only raise new questions but also provide some answers.

scholarly journals Palmitoylated Cysteines in Chikungunya Virus nsP1 Are Critical for Targeting to Cholesterol-Rich Plasma Membrane Microdomains with Functional Consequences for Viral Genome Replication

2020 ◽  
Vol 94 (10) ◽  
Author(s):  
William Bakhache ◽  
Aymeric Neyret ◽  
Eric Bernard ◽  
Andres Merits ◽  
Laurence Briant
Keyword(s):  
Plasma Membrane ◽  
Lipid Bilayers ◽  
Functional Role ◽  
Membrane Microdomains ◽  
Genome Replication ◽  
Functional Importance ◽  
Late Endosomes ◽  
Plasma Membrane Microdomains ◽  
Insight Into

ABSTRACT In mammalian cells, alphavirus replication complexes are anchored to the plasma membrane. This interaction with lipid bilayers is mediated through the viral methyl/guanylyltransferase nsP1 and reinforced by palmitoylation of cysteine residue(s) in the C-terminal region of this protein. Lipid content of membranes supporting nsP1 anchoring remains poorly studied. Here, we explore the membrane binding capacity of nsP1 with regard to cholesterol. Using the medically important chikungunya virus (CHIKV) as a model, we report that nsP1 cosegregates with cholesterol-rich detergent-resistant membrane microdomains (DRMs), also called lipid rafts. In search for the critical factor for cholesterol partitioning, we identify nsP1 palmitoylated cysteines as major players in this process. In cells infected with CHIKV or transfected with CHIKV trans-replicase plasmids, nsP1, together with the other nonstructural proteins, are detected in DRMs. While the functional importance of CHIKV nsP1 preference for cholesterol-rich membrane domains remains to be determined, we observed that U18666A- and imipramine-induced sequestration of cholesterol in late endosomes redirected nsP1 to these compartments and simultaneously dramatically decreased CHIKV genome replication. A parallel study of Sindbis virus (SINV) revealed that nsP1 from this divergent alphavirus displays a low affinity for cholesterol and only moderately segregates with DRMs. Behaviors of CHIKV and SINV with regard to cholesterol, therefore, match with the previously reported differences in the requirement for nsP1 palmitoylation, which is dispensable for SINV but strictly required for CHIKV replication. Altogether, this study highlights the functional importance of nsP1 segregation with DRMs and provides new insight into the functional role of nsP1 palmitoylated cysteines during alphavirus replication. IMPORTANCE Functional alphavirus replication complexes are anchored to the host cell membranes through the interaction of nsP1 with the lipid bilayers. In this work, we investigate the importance of cholesterol for such an association. We show that nsP1 has affinity for cholesterol-rich membrane microdomains formed at the plasma membrane and identify conserved palmitoylated cysteine(s) in nsP1 as the key determinant for cholesterol affinity. We demonstrate that drug-induced cholesterol sequestration in late endosomes not only redirects nsP1 to this compartment but also dramatically decreases genome replication, suggesting the functional importance of nsP1 targeting to cholesterol-rich plasma membrane microdomains. Finally, we show evidence that nsP1 from chikungunya and Sindbis viruses displays different sensitivity to cholesterol sequestering agents that parallel with their difference in the requirement for nsP1 palmitoylation for replication. This research, therefore, gives new insight into the functional role of palmitoylated cysteines in nsP1 for the assembly of functional alphavirus replication complexes in their mammalian host.

Hammerhead ribozyme-mediated silencing of the mutant fibrillin-1 of tight skin mouse: Insight into the functional role of mutant fibrillin-1

2006 ◽  
Vol 312 (9) ◽  
pp. 1463-1474 ◽  
Author(s):  
Rajesh P. Menon ◽  
Malini R. Menon ◽  
Xu Shi-Wen ◽  
Elisabetta Renzoni ◽  
George Bou-Gharios ◽  
...  
Keyword(s):  
Functional Role ◽  
Hammerhead Ribozyme ◽  
Tight Skin ◽  
Fibrillin 1 ◽  
Insight Into

MicroRNA: mIR-ly regulators of DNMT?

Blood ◽  
2009 ◽  
Vol 113 (25) ◽  
pp. 6269-6270 ◽  
Author(s):  
Elizabeth A. Griffiths ◽  
Steven D. Gore
Keyword(s):  
Mechanism Of Action ◽  
Functional Role ◽  
Present Evidence ◽  
Pharmacologically Active ◽  
Insight Into

Abstract In this issue of Blood, Garzon and colleagues present evidence for a functional role of miR 29b in controlling DNMT levels in leukemia. Their work may provide insight into the mechanism of action of the azanucleotides and could potentially offer the first pharmacologically active miRNA.

scholarly journals Distinct effects of Q925 mutation on intracellular and extracellular Na+ and K+ binding to the Na+, K+-ATPase

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hang N. Nielsen ◽  
Kerri Spontarelli ◽  
Rikke Holm ◽  
Jens Peter Andersen ◽  
Anja P. Einholm ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Binding Sites ◽  
Functional Role ◽  
Transmembrane Helix ◽  
Binding Properties ◽  
Ion Translocation ◽  
Extracellular Side ◽  
Insight Into

Abstract Three Na+ sites are defined in the Na+-bound crystal structure of Na+, K+-ATPase. Sites I and II overlap with two K+ sites in the K+-bound structure, whereas site III is unique and Na+ specific. A glutamine in transmembrane helix M8 (Q925) appears from the crystal structures to coordinate Na+ at site III, but does not contribute to K+ coordination at sites I and II. Here we address the functional role of Q925 in the various conformational states of Na+, K+-ATPase by examining the mutants Q925A/G/E/N/L/I/Y. We characterized these mutants both enzymatically and electrophysiologically, thereby revealing their Na+ and K+ binding properties. Remarkably, Q925 substitutions had minor effects on Na+ binding from the intracellular side of the membrane – in fact, mutations Q925A and Q925G increased the apparent Na+ affinity – but caused dramatic reductions of the binding of K+ as well as Na+ from the extracellular side of the membrane. These results provide insight into the changes taking place in the Na+-binding sites, when they are transformed from intracellular- to extracellular-facing orientation in relation to the ion translocation process, and demonstrate the interaction between sites III and I and a possible gating function of Q925 in the release of Na+ at the extracellular side.

scholarly journals Crystal structures of human cardiac beta-myosin II S2-  provide insight into the functional role of the S2 subfragment

2006 ◽  
Vol 103 (47) ◽  
pp. 17713-17717 ◽  
Author(s):  
W. Blankenfeldt ◽  
N. H. Thoma ◽  
J. S. Wray ◽  
M. Gautel ◽  
I. Schlichting
Keyword(s):  
Crystal Structures ◽  
Functional Role ◽  
Myosin Ii ◽  
Insight Into

scholarly journals SUMOylome Modulates Intraflagellar Transport Machinery and Eukaryotic Cilia Motility

2021 ◽  
Author(s):  
Komal Sharma ◽  
Irina Sizova ◽  
Girdhar Pandey ◽  
Peter Hegemann ◽  
Suneel Kateriya
Keyword(s):  
Functional Role ◽  
Intraflagellar Transport ◽  
Small Gtpase ◽  
The Other ◽  
Signaling Proteins ◽  
Sumoylation Site ◽  
C Terminus ◽  
First Time ◽  
Insight Into

Abstract Translocation of channelrhodopsins (ChRs) is mediated by intraflagellar transport (IFT) machinery. However, the functional role of the network containing photoreceptors, IFT and other proteins in controlling cilia motility of the alga is still not fully delineated. In the current study, we identified two important motifs at the C-terminus of ChR1. One of them is similar to a known ciliary targeting sequence that specifically interacts with a small GTPase, and the other is a SUMOylation site. For the first time, experimental data provide an insight into the role of SUMOylation in the modulation of IFT & ChR1. Blocking of SUMOylation affected the phototaxis of C. reinhardtii cells. This implies SUMOylation based regulation of protein network controlling photomotility. The conservation of SUMOylation site pattern as analyzed for the relevant photoreceptors, IFT and its associated signaling proteins in other ciliated green algae suggested SUMOylation based photobehavioural response across the microbes. This report establishes a link between evolutionary conserved SUMOylation and ciliary machinery for the maintenance and functioning of cilia across the eukaryotes. Our enriched SUMOylome of C. reinhardtii comprehends the proteins related to ciliary development and, photo-signaling, along with homologue(s) associated to human ciliopathies as SUMO targets.

Structure of peptidyl-tRNA hydrolase 2 fromPyrococcus horikoshiiOT3: insight into the functional role of its dimeric state

2008 ◽  
Vol 64 (4) ◽  
pp. 444-453 ◽  
Author(s):  
Katsumi Shimizu ◽  
Chizu Kuroishi ◽  
Mitsuaki Sugahara ◽  
Naoki Kunishima
Keyword(s):  
Functional Role ◽  
Insight Into
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