The evolutionary aspects of aquaporin family

2011 ◽  
Vol 300 (3) ◽  
pp. R566-R576 ◽  
Author(s):  
Kenichi Ishibashi ◽  
Shintaro Kondo ◽  
Shigeki Hara ◽  
Yoshiyuki Morishita
Keyword(s):  
Water Transport ◽  
Cell Volume Regulation ◽  
Fluid Secretion ◽  
Cysteine Residue ◽  
Amino Acid Sequences ◽  
Glycerol Transport ◽  
Signature Sequences ◽  
Intracellular Organelles ◽  
Evolutionary Aspects ◽  
Aquaporin Family

Aquaporins (AQPs) were originally identified as channels facilitating water transport across the plasma membrane. They have a pair of highly conserved signature sequences, asparagine-proline-alanine (NPA) boxes, to form a pore. However, some have little conserved amino acid sequences around the NPA boxes unclassifiable to two previous AQP subfamilies, classical AQPs and aquaglyceroporins. These will be called unorthodox AQPs in this review. Interestingly, these unorthodox AQPs have a highly conserved cysteine residue downstream of the second NPA box. AQPs also have a diversity of functions: some related to water transport such as fluid secretion, fluid absorption, and cell volume regulation, and the others not directly related to water transport such as cell adhesion, cell migration, cell proliferation, and cell differentiation. Some AQPs even permeate nonionic small molecules, ions, metals, and possibly gasses. AQP gene disruption studies have revealed their physiological roles: water transport in the kidney and exocrine glands, glycerol transport in fat metabolism and in skin moisture, and nutrient uptakes in plants. Furthermore, AQPs are also present at intracellular organelles, including tonoplasts, mitochondria, and the endoplasmic reticulum. This review focuses on the evolutionary aspects of AQPs from bacteria to humans in view of the structural and functional diversities of AQPs.

The Evolutionary Aspects of Aquaporin Family

2017 ◽  
pp. 35-50 ◽  
Author(s):  
Kenichi Ishibashi ◽  
Yoshiyuki Morishita ◽  
Yasuko Tanaka
Keyword(s):  
Evolutionary Aspects ◽  
Aquaporin Family

Intestinal nerves and ion transport: stimuli, reflexes, and responses

1985 ◽  
Vol 248 (3) ◽  
pp. G261-G271 ◽  
Author(s):  
K. A. Hubel
Keyword(s):  
Small Intestine ◽  
Ion Transport ◽  
Water Transport ◽  
Sensory Cell ◽  
Venous Blood ◽  
Extracellular Fluid ◽  
Fluid Secretion ◽  
Alkaline Secretion

The effects of extrinsic and intrinsic nerves on ion and water transport by the intestine are considered and discussed in terms of their possible physiological function. Adrenergic nerves enter the small intestine via mesenteric nerves. Adrenergic tone is usually absent in tissues in vitro but is present in vivo. The nerves increase absorption in response to homeostatic changes associated with acute depletion of extracellular fluid. Cholinergic tone that reduces fluid absorption or causes secretion has been detected in the small intestine of humans, dogs, and cats and in the colon of humans. Extrinsic cholinergic fibers generally do not affect ion transport in small intestine but probably do so in colon. Whether peptides liberated in the mucosa affect enterocytes directly is not clear. Studies on humans and rabbits suggest that the role of substance P is minor. The physiological roles of vasoactive intestinal polypeptide (VIP) and somatostatin remain to be defined. Intraluminal factors also affect ion and water transport. Mucosal rubbing, distension, and cholera toxin cause fluid secretion; acid solutions in the duodenum cause alkaline secretion; these stimuli and hypertonic glucose liberate serotonin into the lumen, the mesenteric venous blood, or both. It has been proposed that the enterochromaffin cell is an epithelial sensory cell that responds to noxious stimuli within the lumen by liberating serotonin. The serotonin initiates a neural reflex through a nicotinic ganglion to liberate a secretagogue that acts on the enterocyte. The function of VIP in this proposed reflex is unclear. The variety of intraluminal stimuli that influence epithelial function implies that there is more than one type of epithelial sensory cell (or sensory mechanism). Prostaglandins may mediate the alkaline secretion caused by acid in the duodenum. There may be other effective substances. Although it has been known for years that intraluminal stimuli affect the coordination of smooth muscle functions, it is not known whether similar stimuli also influence salt and water transport as a meal traverses the alimentary canal.

Investigation of subtilisin digest of pepsin chain between half-cystines II and III

1981 ◽  
Vol 46 (3) ◽  
pp. 640-654
Author(s):  
Vladimír Kostka
Keyword(s):  
Amino Acid ◽  
Paper Chromatography ◽  
Sequential Analysis ◽  
Cysteine Residue ◽  
Amino Acid Sequences ◽  
Tryptic Digestion ◽  
Hydrolysis Of ◽  
Dowex 1 ◽  
Final Purification

Aminoethylated hog pepsin was subjected to tryptic digestion and the longest fragment, arising from cleavage at S-(β-aminoethyl)-cysteine residue No II and III was isolated from the digest. This fragment was subjected to additional cleavage with subtilisin and the digest resolved into crude fractions by chromatography on Dowex 1. The isolation and final purification of the peptides was carried out by paper electrophoreses and paper chromatography. By these methods 55 peptides were obtained which were subjected to sequential analysis by stepwise degradation. The amino acid sequences of these peptides and their position in the pepsin chain are given. These sequences provided overlaps for peptides obtained by hydrolysis of this part of the pepsin chain by other enzymes.

scholarly journals Generation of WNK1 knockout cell lines by CRISPR/Cas-mediated genome editing

2015 ◽  
Vol 308 (4) ◽  
pp. F366-F376 ◽  
Author(s):  
Ankita Roy ◽  
Joshua H. Goodman ◽  
Gulnaz Begum ◽  
Bridget F. Donnelly ◽  
Gabrielle Pittman ◽  
...  
Keyword(s):  
Cell Volume ◽  
Cell Lines ◽  
Mammalian Cells ◽  
Cell Volume Regulation ◽  
Fluid Secretion ◽  
Salt Transport ◽  
Simple Method ◽  
Knock Out ◽  
Hypertonic Stress ◽  
Wnk Kinases

Sodium-coupled SLC12 cation chloride cotransporters play important roles in cell volume and chloride homeostasis, epithelial fluid secretion, and renal tubular salt reabsorption. These cotransporters are phosphorylated and activated indirectly by With-No-Lysine (WNK) kinases through their downstream effector kinases, Ste20- and SPS1-related proline alanine-rich kinase (SPAK) and oxidative stress-responsive kinase 1 (OSR1). Multiple WNK kinases can coexist within a single cell type, although their relative contributions to SPAK/OSR1 activation and salt transport remain incompletely understood. Deletion of specific WNKs from cells that natively express a functional WNK-SPAK/OSR1 network will help resolve these knowledge gaps. Here, we outline a simple method to selectively knock out full-length WNK1 expression from mammalian cells using RNA-guided clustered regularly interspaced short palindromic repeats/Cas9 endonucleases. Two clonal cell lines were generated by using a single-guide RNA (sgRNA) targeting exon 1 of the WNK1 gene, which produced indels that abolished WNK1 protein expression. Both cell lines exhibited reduced endogenous WNK4 protein abundance, indicating that WNK1 is required for WNK4 stability. Consistent with an on-target effect, the reduced WNK4 abundance was associated with increased expression of the KLHL3/cullin-3 E3 ubiquitin ligase complex and was rescued by exogenous WNK1 overexpression. Although the morphology of the knockout cells was indistinguishable from control, they exhibited low baseline SPAK/OSR1 activity and failed to trigger regulatory volume increase after hypertonic stress, confirming an essential role for WNK1 in cell volume regulation. Collectively, our data show how this new, powerful, and accessible gene-editing technology can be used to dissect and analyze WNK signaling networks.

scholarly journals Sequence Diversity of Bacillus thuringiensis Flagellin (H Antigen) Protein at the Intra-H Serotype Level

2008 ◽  
Vol 74 (17) ◽  
pp. 5524-5532 ◽  
Author(s):  
Dong Xu ◽  
Jean-Charles Côté
Keyword(s):  
Amino Acid ◽  
Bacillus Thuringiensis ◽  
Variable Region ◽  
Single Copy ◽  
Amino Acid Sequences ◽  
Sequence Diversity ◽  
Neighbor Joining ◽  
Signature Sequences ◽  
Short Signature ◽  
H Serotypes

ABSTRACT In Bacillus thuringiensis, the hag gene encodes flagellin, the protein responsible for eliciting the immunological reaction in H serotyping. Specific flagellin amino acid sequences have been correlated to specific B. thuringiensis H serotypes, H1 to H67. Ten H serotypes, however, contain three or more antigenic subfactors, labeled a, b, c, d, or e, and have been subdivided into 23 serovars. In the present study, we set out to analyze the sequence diversity of flagellins among serovars from the same H serotypes. We studied the hag genes in 39 B. thuringiensis strains representing the 23 serovars from the 10 H serotypes mentioned above. A serovar and a biovar from an 11th H serotype were also included. The hag genes were amplified and cloned and their nucleotide sequences were determined and translated into amino acid sequences, or the sequences were retrieved directly from GenBank when available. Strains of the H3 serotype contained two or three copies of the fla gene, an ortholog of the hag gene. Strains of the H6 serotype contained three copies. Strains of all other H serotypes each contained a single copy of the hag gene. Alignments of amino acid sequences from all copies in all strains of the H3 serotype revealed short signature sequences, GGAG and SGG, GPDPDDAVKNLT, and DITTTK, that appeared to be specific to the H3c, H3d, and H3e antigenic subfactors, respectively. Similar short signature sequences, GDIT, AFIK, TSAGKA, and SAPSKG, were revealed for H8b, H8c, H20b, and H20c, respectively. Amino acid sequences in the flagellin central variable region were highly conserved among serovars of the H3, H5, H11, and H20 serotypes and much more divergent among serovars of the H4, H10, H18, H24, and H28 serotypes. Two bootstrapped neighbor-joining trees were respectively generated from the alignments of the amino acid sequences translated from all copies of the hag genes in the B. thuringiensis strains of the H3 and H6 serotypes. Sequence identities and relationships were revealed. A third bootstrapped neighbor-joining tree was generated, this one from the alignment of the flagellin amino acid sequences from all the B. thuringiensis strains in the study. Eight clusters, I to VIII, were revealed. Although most clusters contained strains and serovars from the same H serotype, clusters VII and VIII contained serovars from different H serotypes.

scholarly journals Allele Variants of Enterotoxigenic Escherichia coli Heat-Labile Toxin Are Globally Transmitted and Associated with Colonization Factors

2014 ◽  
Vol 197 (2) ◽  
pp. 392-403 ◽  
Author(s):  
Enrique Joffré ◽  
Astrid von Mentzer ◽  
Moataz Abd El Ghany ◽  
Numan Oezguen ◽  
Tor Savidge ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Fluid Secretion ◽  
Toxin Production ◽  
Amino Acid Sequences ◽  
Enterotoxigenic Escherichia Coli ◽  
Content Type ◽  
Heat Labile ◽  
Virulence Potential ◽  
Colonization Factors

EnterotoxigenicEscherichia coli(ETEC) is a significant cause of morbidity and mortality in the developing world. ETEC-mediated diarrhea is orchestrated by heat-labile toxin (LT) and heat-stable toxins (STp and STh), acting in concert with a repertoire of more than 25 colonization factors (CFs). LT, the major virulence factor, induces fluid secretion after delivery of a monomeric ADP-ribosylase (LTA) and its pentameric carrier B subunit (LTB). A study of ETEC isolates from humans in Brazil reported the existence of natural LT variants. In the present study, analysis of predicted amino acid sequences showed that the LT amino acid polymorphisms are associated with a geographically and temporally diverse set of 192 clinical ETEC strains and identified 12 novel LT variants. Twenty distinct LT amino acid variants were observed in the globally distributed strains, and phylogenetic analysis showed these to be associated with different CF profiles. Notably, the most prevalent LT1 allele variants were correlated with major ETEC lineages expressing CS1 + CS3 or CS2 + CS3, and the most prevalent LT2 allele variants were correlated with major ETEC lineages expressing CS5 + CS6 or CFA/I. LTB allele variants generally exhibited more-stringent amino acid sequence conservation (2 substitutions identified) than LTA allele variants (22 substitutions identified). The functional impact of LT1 and LT2 polymorphisms on virulence was investigated by measuring total-toxin production, secretion, and stability using GM1–enzyme-linked immunosorbent assays (GM1-ELISA) andin silicoprotein modeling. Our data show that LT2 strains produce 5-fold more toxin than LT1 strains (P< 0.001), which may suggest greater virulence potential for this genetic variant. Our data suggest that functionally distinct LT-CF variants with increased fitness have persisted during the evolution of ETEC and have spread globally.

scholarly journals Amino acid sequences around the cysteine residue of calf lens α-crystallin

1971 ◽  
Vol 124 (1) ◽  
pp. 61-67 ◽  
Author(s):  
P. H. Corran ◽  
S. G. Waley
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Thiol Group ◽  
Cysteine Residue ◽  
Amino Acid Sequences ◽  
Amino Acid Residues ◽  
Radioactive Sodium ◽  
Group 2

1. Calf lens α-crystallin was carboxymethylated with radioactive sodium iodoacetate to label the thiol group. 2. The protein was then digested with trypsin or alternatively fractionated in urea to obtain the acidic (A) chains, which were then digested with trypsin. Either procedure gave two radioactive peptides containing carboxymethylcysteine. 3. These two peptides were closely related: the longer form contained 28 amino acid residues, and the shorter lacked two residues at the N-terminal end of the longer form. 4. The amino acid sequence of the peptides have been determined. 5. No evidence for the presence of more than one cysteine residue/chain was found. 6. The question of the molecular weight of the chains is discussed.

scholarly journals The ATP-Releasing Maxi-Cl Channel: Its Identity, Molecular Partners, and Physiological/Pathophysiological Implications

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 509
Author(s):  
Ravshan Z. Sabirov ◽  
Md. Rafiqul Islam ◽  
Toshiaki Okada ◽  
Petr G. Merzlyak ◽  
Ranokhon S. Kurbannazarova ◽  
...  
Keyword(s):  
Calcium Binding ◽  
Cardiac Myocyte ◽  
Cell Volume Regulation ◽  
Anion Channel ◽  
Fluid Secretion ◽  
Activation Mechanism ◽  
Anion Channels ◽  
Cation Selectivity ◽  
Cl Channel ◽  
Voltage Relationship

The Maxi-Cl phenotype accounts for the majority (app. 60%) of reports on the large-conductance maxi-anion channels (MACs) and has been detected in almost every type of cell, including placenta, endothelium, lymphocyte, cardiac myocyte, neuron, and glial cells, and in cells originating from humans to frogs. A unitary conductance of 300–400 pS, linear current-to-voltage relationship, relatively high anion-to-cation selectivity, bell-shaped voltage dependency, and sensitivity to extracellular gadolinium are biophysical and pharmacological hallmarks of the Maxi-Cl channel. Its identification as a complex with SLCO2A1 as a core pore-forming component and two auxiliary regulatory proteins, annexin A2 and S100A10 (p11), explains the activation mechanism as Tyr23 dephosphorylation at ANXA2 in parallel with calcium binding at S100A10. In the resting state, SLCO2A1 functions as a prostaglandin transporter whereas upon activation it turns to an anion channel. As an efficient pathway for chloride, Maxi-Cl is implicated in a number of physiologically and pathophysiologically important processes, such as cell volume regulation, fluid secretion, apoptosis, and charge transfer. Maxi-Cl is permeable for ATP and other small signaling molecules serving as an electrogenic pathway in cell-to-cell signal transduction. Mutations at the SLCO2A1 gene cause inherited bone and gut pathologies and malignancies, signifying the Maxi-Cl channel as a perspective pharmacological target.

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