scholarly journals Syntaxin 17, an ancient SNARE paralog, plays different and conserved roles in different organisms

2021 ◽  
Author(s):  
Shun Kato ◽  
Kohei Arasaki ◽  
Natsuki Tokutomi ◽  
Yuzuru Imai ◽  
Tsuyoshi Inoshita ◽  
...  
Keyword(s):  
Amino Acid ◽  
Membrane Fusion ◽  
Basic Amino Acid ◽  
The Other ◽  
Autophagosome Formation ◽  
Hydrophobic Region ◽  
Mitochondrial Division ◽  
Eukaryotic Organisms ◽  
And Function ◽  
Insight Into

Mammalian syntaxin 17 (Stx17) has several functions, other than membrane fusion, including mitochondrial division, autophagosome formation and lipid droplet expansion. Different from conventional syntaxins, Stx17 has a long C-terminal hydrophobic region with a hairpin-like structure flanked by a basic amino acid-enriched C-terminal tail. Although Stx17 is one of the six ancient SNAREs and present in diverse eukaryotic organisms, it has been lost in multiple lineages during evolution. In the present study, we compared the localization and function of fly and nematode Stx17s expressed in HeLa cells with those of human Stx17. We found that fly Stx17 predominantly localizes to the cytosol and mediates autophagy, but not mitochondrial division. Nematode Stx17, on the other hand, is predominantly present in mitochondria and facilitates mitochondrial division, but is irrelevant to autophagy. These differences are likely due to different structures in the C-terminal tail. Non-participation of fly Stx17 and nematode Stx17 in mitochondrial division and autophagy, respectively, was demonstrated in individual organisms. Our results provide an insight into the evolution of Stx17 in metazoa.

scholarly journals Evolutionary Analyses of ABC Transporters of Dictyostelium discoideum

2002 ◽  
Vol 1 (4) ◽  
pp. 643-652 ◽  
Author(s):  
Christophe Anjard ◽  
William F. Loomis
Keyword(s):  
Amino Acid ◽  
Dictyostelium Discoideum ◽  
Abc Transporters ◽  
Sequence Homology ◽  
Genome Project ◽  
The Other ◽  
Atp Binding ◽  
And Function ◽  
Insight Into ◽  
Atp Binding Cassette

ABSTRACT The ABC superfamily of genes is one of the largest in the genomes of both bacteria and eukaryotes. The proteins encoded by these genes all carry a characteristic 200- to 250-amino-acid ATP-binding cassette that gives them their family name. In bacteria they are mostly involved in nutrient import, while in eukaryotes many are involved in export. Seven different families have been defined in eukaryotes based on sequence homology, domain topology, and function. While only 6 ABC genes in Dictyostelium discoideum have been studied in detail previously, sequences from the well-advanced Dictyostelium genome project have allowed us to recognize 68 members of this superfamily. They have been classified and compared to animal, plant, and fungal orthologs in order to gain some insight into the evolution of this superfamily. It appears that many of the genes inferred to have been present in the ancestor of the crown organisms duplicated extensively in some but not all phyla, while others were lost in one lineage or the other.

Comparison of the Potency of 8-L-Arginine, 8-D-Arginine and 8-D-Homoarginine Vasopressin Analogs with Substituted Phenylalanine in Position 2

1994 ◽  
Vol 59 (6) ◽  
pp. 1439-1450 ◽  
Author(s):  
Miroslava Žertová ◽  
Jiřina Slaninová ◽  
Zdenko Procházka
Keyword(s):  
Amino Acid ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Basic Amino Acid ◽  
The Other ◽  
Side Chain ◽  
Inhibitory Potency ◽  
Phase Synthesis ◽  
Other Hand ◽  
Order Of Magnitude

An analysis of the uterotonic potencies of all analogs having substituted L- or D-tyrosine or -phenylalanine in position 2 and L-arginine, D-arginine or D-homoarginine in position 8 was made. The series of analogs already published was completed by the solid phase synthesis of ten new analogs having L- or D-Phe, L- or D-Phe(2-Et), L- or D-Phe(2,4,6-triMe) or D-Tyr(Me) in position 2 and either L- or D-arginine in position 8. All newly synthesized analogs were found to be uterotonic inhibitors. Deamination increases both the agonistic and antagonistic potency. In the case of phenylalanine analogs the change of configuration from L to D in position 2 enhances the uterotonic inhibition for more than 1 order of magnitude. The L to D change in position 8 enhances the inhibitory potency negligibly. Prolongation of the side chain of the D-basic amino acid in position 8 seems to decrease slightly the inhibitory potency if there is L-substituted amino acid in position 2. On the other hand there is a tendency to the increase of the inhibitory potency if there is D-substituted amino acid in position 2.

scholarly journals Differential expression of two somatostatin receptor subtype 1 mRNAs in rainbow trout (Oncorhynchus mykiss)

2004 ◽  
Vol 32 (1) ◽  
pp. 165-177 ◽  
Author(s):  
BJ Slagter ◽  
MA Sheridan
Keyword(s):  
Rainbow Trout ◽  
Amino Acid ◽  
Somatostatin Receptor ◽  
The Other ◽  
Receptor Subtype ◽  
Signaling System ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Lower Intestine ◽  
Growth Development ◽  
Insight Into

Somatostatins (SSs) play important roles in the growth, development and metabolism of vertebrates. In this study, cDNAs for two unique somatostatin receptor variants were cloned and sequenced from rainbow trout. The two cDNAs, one consisting of 1755 bp and the other of 1743 bp, share 63.6% identity in nucleotide sequence and 94.1% identity in deduced amino acid sequence and presumably arose through gene duplication. Each cDNA encodes for a putative 371-amino acid somatostatin receptor (one designated sst1A and the other sst1B) containing seven transmembrane domains. Rainbow trout sst1A and sst1B have 64.4 and 65.5% similarity respectively with human sst1 and only 43-60% similarity with other subtypes. Trout sst1 mRNAs are differentially expressed, both in terms of distribution among tissues as well as in terms of abundance within selected tissues. Both sst1A and sst1B mRNAs were present in brain, stomach, liver, pancreas, upper and lower intestine, pyloric cecum, kidney and muscle, whereas only sst1B mRNA was present in the esophagus. sst1A mRNA was more abundant than sst1B in the optic tectum, whereas sst1B mRNA was more abundant than sst1A in liver. sst1A and sst1B mRNAs were equally abundant in pancreas. These findings contribute to the understanding of the evolution of the SS signaling system and provide insight into the mechanisms that regulate the expression of SS receptors.

scholarly journals Representation and function of characters from Greek antiquity in Benjamin Britten’s Death in Venice

Literator ◽  
2002 ◽  
Vol 23 (1) ◽  
pp. 1-18 ◽  
Author(s):  
B. Spies
Keyword(s):  
The Other ◽  
Focal Points ◽  
Other Hand ◽  
Death In Venice ◽  
The One ◽  
And Function ◽  
Insight Into

Lack of insight into Greek antiquity, more specifically the nature of classical tragedy and mythology, could be one reason for the negative reception of Benjamin Britten’s last opera Death in Venice. In the first place, this article considers Britten’s opera based on Thomas Mann’s novella as a manifestation of classical tragedy. Secondly, it is shown how mythological characters in Mann’s novella represent abstract ideas2 in Britten’s opera, thereby enhancing the dramatic impact of the opera considerably. On the one hand it is shown how the artist’s inner conflict manifests itself in a dialectic relationship between discipline and inspirat ion in Plato’s Phaedrus dialogue that forms the basis of Aschenbach’s monologue at the end of the opera. The conflict between Aschenbach’s rational consciousness and his irrational subconscious, on the other hand, is depicted by means of mythological figures, Apollo and Dionysus. Two focal points in the opera, namely the Games of Apollo at the end of Act 1 and the nightmare scene which forms the climax of the opera in Act 2, are used to illustrate the musical manifestation of this conflict.

scholarly journals Membrane barrels are taller, fatter, inside-out soluble barrels

2021 ◽  
Author(s):  
Rik Dhar ◽  
Ryan Feehan ◽  
Joanna S.G. Slusky
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Outer Membrane ◽  
Acid Composition ◽  
Relative Size ◽  
And Function ◽  
Inside Out ◽  
Insight Into ◽  
Regular Alternation

AbstractUp-and-down β-barrel topology exists in both the membrane and soluble environment. However, β-barrels are virtually the only topology that exist in the outer membrane. By comparing features of these structurally similar proteins, we can determine what features are particular to the environment rather than the fold. Here we compare structures of membrane β-barrels to soluble β-barrels and evaluate their relative size, shape, amino acid composition, hydrophobicity, and periodicity. We find that membrane β-barrels are generally larger than soluble β-barrels in with more strands per barrel and more amino acids per strand, making them wider and taller. We also find that membrane β-barrels are inside-out soluble β-barrels. The inward region of membrane β-barrels have similar hydrophobicity to the outward region of soluble β-barrels, and the outward region of membrane β-barrels has similar hydrophobicity to the inward region of the soluble β-barrels. Moreover, even though both types of β-barrel have been assumed to have strands with amino acids that alternate in direction and hydrophobicity, we find that the membrane β-barrels have more regular alternation than soluble β-barrels. These features give insight into how membrane barrels maintain their fold and function in the membrane.

scholarly journals Ancient art, rhetoric and the Lamb of God metaphor in John 1:29 and 1:36

2015 ◽  
Vol 71 (1) ◽  
Author(s):  
Lilly Nortjé-Meyer
Keyword(s):  
Alternative Interpretation ◽  
The Other ◽  
Fourth Gospel ◽  
John 1 ◽  
And Function ◽  
Meaning And Function ◽  
Insight Into ◽  
Story Elements

Biblical scholars have given diverse explanations for the Lamb of God metaphor in John 1:29 and 1:36. Most scholars are of the opinion that ‘amnos’ refers to the Passover lamb. This explanation is not obvious from the context of the Fourth Gospel. To understand the metaphor ‘lamb’ or ‘amnos’ of God, one should understand the transferable meaning of the figure or image. In this comparison, only the vehicle, namely the lamb, is given. What and who the lamb is stays open. It can be anything within the limits of the other story elements that have the same qualities as a lamb. To uncover the communicative dynamics of the metaphor, the exegete must have insight into the meaning and function of the original metaphor. Rhetoric provides a clue for the interpretation of the metaphor, namely that it is a Lamb of God. Within the pericope other rhetorical clues like antithesis and varietas are also provided. These clues are important but do not explain the image of the lamb. In this study, these problems will be considered via another medium, namely Hellenistic art and imagesand their penetration into Judaism and Christianity during the 1st century CE. Hellenistic and biblical images will be used to give an alternative interpretation of the metaphor of the Lamb of God.

A tale of two charges: Distinct roles for an acidic and a basic amino acid in the structure and function of cytochrome c

2001 ◽  
Vol 79 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Jonathan C. Parrish ◽  
J. Guy Guillemette ◽  
Carmichael J.A. Wallace
Keyword(s):  
Amino Acid ◽  
Basic Amino Acid ◽  
Structure And Function ◽  
And Function

scholarly journals Primordial emergence of a nucleic acid binding protein via phase separation and statistical ornithine to arginine conversion

2020 ◽  
Author(s):  
Liam M. Longo ◽  
Dragana Despotović ◽  
Orit Weil-Ktorza ◽  
Matthew J. Walker ◽  
Jagoda Jabłońska ◽  
...  
Keyword(s):  
Phase Separation ◽  
Amino Acid ◽  
De Novo ◽  
Binding Protein ◽  
Basic Amino Acid ◽  
Structure And Function ◽  
Nucleic Acid Binding ◽  
And Function ◽  
Structured Proteins ◽  
Dsdna Binding

AbstractDe novo emergence, and emergence of the earliest proteins specifically, demands a transition from disordered polypeptides into structured proteins with well-defined functions. However, can peptides confer evolutionary relevant functions, let alone with minimal abiotic amino acid alphabets? How can such polypeptides evolve into mature proteins? Specifically, while nucleic acids binding is presumed a primordial function, it demands basic amino acids that do not readily form abiotically. To address these questions, we describe an experimentally-validated trajectory from a phase-separating polypeptide to a dsDNA-binding protein. The intermediates comprise sequence-duplicated, functional proteins made of only 10 amino acid types, with ornithine, which can form abiotically, as the only basic amino acid. Statistical, chemical modification of ornithine sidechains to arginine promoted structure and function. The function concomitantly evolved – from phase separation with RNA (coacervates) to avid and specific dsDNA binding – thereby demonstrating a smooth, gradual peptide-to-protein transition with respect to sequence, structure, and function.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

A Bird in the Hand Isn’t Good for Long

2018 ◽  
Vol 65 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Stefan Scherbaum ◽  
Simon Frisch ◽  
Maja Dshemuchadse
Keyword(s):  
Decision Making ◽  
Cognitive Control ◽  
The Other ◽  
Decision Task ◽  
Short Term ◽  
Additional Time ◽  
Control Processes ◽  
Folk Wisdom ◽  
Study Participants ◽  
Insight Into

Abstract. Folk wisdom tells us that additional time to make a decision helps us to refrain from the first impulse to take the bird in the hand. However, the question why the time to decide plays an important role is still unanswered. Here we distinguish two explanations, one based on a bias in value accumulation that has to be overcome with time, the other based on cognitive control processes that need time to set in. In an intertemporal decision task, we use mouse tracking to study participants’ responses to options’ values and delays which were presented sequentially. We find that the information about options’ delays does indeed lead to an immediate bias that is controlled afterwards, matching the prediction of control processes needed to counter initial impulses. Hence, by using a dynamic measure, we provide insight into the processes underlying short-term oriented choices in intertemporal decision making.

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