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Jochen Lang - One of the best experts on this subject based on the ideXlab platform.
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The Variable C-Terminus of Cysteine String Proteins Modulates Exocytosis and Protein−Protein Interactions†
Biochemistry, 2004Co-Authors: Frédéric Boal, P Scotti, Céline Tessier, Hui Zhang, Jochen LangAbstract:Cysteine string proteins (Csps) are vesicle proteins involved in neurotransmission and hormone exocytosis. They are composed of distinct domains: a variable N-Terminus, a J-domain followed by a linker region, a cysteine-rich string, and a C-terminus which diverges among isoforms. Their precise function and interactions are not fully understood. Using insulin exocytosis as a model, we show that the linker region and the C-terminus, but not the variable N-Terminus, regulate overall secretion. Moreover, endogenous Csp1 binds in a calcium-dependent manner to monomeric VAMP2, and this interaction requires the C-terminus of Csp. The interaction is isoform specific as recombinant Csp1 binds VAMP1 and VAMP7, but not VAMP3. Cross-linking in permeabilized clonal β-cells revealed homodimerization of Csp which is stimulated by Ca2+ and again modulated by the variant C-terminus. Our data suggest that both interactions of Csp occur during exocytosis and may explain the effect of the variant C-terminus of this chaperon...
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The variable C-terminus of cysteine string proteins modulates exocytosis and protein-protein interactions.
Biochemistry, 2004Co-Authors: Frédéric Boal, P Scotti, Céline Tessier, Hui Zhang, Jochen LangAbstract:Cysteine string proteins (Csps) are vesicle proteins involved in neurotransmission and hormone exocytosis. They are composed of distinct domains: a variable N-Terminus, a J-domain followed by a linker region, a cysteine-rich string, and a C-terminus which diverges among isoforms. Their precise function and interactions are not fully understood. Using insulin exocytosis as a model, we show that the linker region and the C-terminus, but not the variable N-Terminus, regulate overall secretion. Moreover, endogenous Csp1 binds in a calcium-dependent manner to monomeric VAMP2, and this interaction requires the C-terminus of Csp. The interaction is isoform specific as recombinant Csp1 binds VAMP1 and VAMP7, but not VAMP3. Cross-linking in permeabilized clonal β-cells revealed homodimerization of Csp which is stimulated by Ca2+ and again modulated by the variant C-terminus. Our data suggest that both interactions of Csp occur during exocytosis and may explain the effect of the variant C-terminus of this chaperon...
Sylvia Daunert - One of the best experts on this subject based on the ideXlab platform.
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An Immunoassay for Leu-enkephalin Based on a C-Terminal Aequorin−Peptide Fusion
Analytical Chemistry, 2001Co-Authors: Sylvia DaunertAbstract:Recently we demonstrated that the fusion of an octapeptide to the C-terminus of a cysteine-free mutant of aequorin showed no inhibitory effect on the luminescence activity of the photoprotein. This observation is of particular importance when the use of aequorin as a label in the development of immunoassays for peptides whose activity lies in their C-terminal region or the epitope for antibody recognition is at their C-terminus is desired. In the case of opioid peptides, antibodies are directed toward their C-terminus as they differ from each other at this terminus. The goal of this study was to develop an immunoassay for Leu-enkephalin, a mammalian opioid peptide, using a C-terminal aequorin−peptide fusion protein. For that, the N-Terminus of Leu-enkephalin was genetically fused to the C-terminus of a cysteine-free mutant of aequorin. It was observed that the C-terminal conjugated aequorin maintained its luminescence activity. An immunoassay for Leu-enkephalin was then developed using the aequorin−Leu-en...
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An immunoassay for Leu-enkephalin based on a C-terminal aequorin-peptide fusion.
Analytical chemistry, 2001Co-Authors: Sapna K. Deo, Sylvia DaunertAbstract:Recently we demonstrated that the fusion of an octapeptide to the C-terminus of a cysteine-free mutant of aequorin showed no inhibitory effect on the luminescence activity of the photoprotein. This observation is of particular importance when the use of aequorin as a label in the development of immunoassays for peptides whose activity lies in their C-terminal region or the epitope for antibody recognition is at their C-terminus is desired. In the case of opioid peptides, antibodies are directed toward their C-terminus as they differ from each other at this terminus. The goal of this study was to develop an immunoassay for Leu-enkephalin, a mammalian opioid peptide, using a C-terminal aequorin−peptide fusion protein. For that, the N-Terminus of Leu-enkephalin was genetically fused to the C-terminus of a cysteine-free mutant of aequorin. It was observed that the C-terminal conjugated aequorin maintained its luminescence activity. An immunoassay for Leu-enkephalin was then developed using the aequorin−Leu-en...
Michael J. Welsh - One of the best experts on this subject based on the ideXlab platform.
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Mechanism by which Liddle's syndrome mutations increase activity of a human epithelial Na+ channel
Cell, 1995Co-Authors: Peter M. Snyder, Margaret P. Price, Fiona J. Mcdonald, Christopher M. Adams, Kenneth A. Volk, Bernhardt G. Zeiher, John B. Stokes, Michael J. WelshAbstract:Abstract Liddle's syndrome is an inherited form of hypertension caused by mutations that truncate the C-terminus of human epithelial Na + channel (hENaC) subunits. Expression of truncated β and γ hENaC subunits increased Na + current. However, truncation did not alter single-channel conductance or open state probability, suggesting there were more channels in the plasma membrane. Moreover, truncation of the C-terminus of the β subunit increased apical cell-surface expression of hENaC in a renal epithelium. We identified a conserved motif in the C-terminus of all three subunits that, when mutated, reproduced the effect of Liddle's truncations. Further, both truncation of the C-terminus and mutation of the conserved C-terminal motif increased surface expression of chimeric proteins containing the C-terminus of β hENaC. Thus, by deleting a conserved motif, Liddle's mutations increase the number of Na + channels in the apical membrane, which increases renal Na + absorption and creates a predisposition to hypertension.
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mechanism by which liddle s syndrome mutations increase activity of a human epithelial na channel
Cell, 1995Co-Authors: Peter M. Snyder, Margaret P. Price, Fiona J. Mcdonald, Christopher M. Adams, Kenneth A. Volk, Bernhardt G. Zeiher, John B. Stokes, Michael J. WelshAbstract:Abstract Liddle's syndrome is an inherited form of hypertension caused by mutations that truncate the C-terminus of human epithelial Na + channel (hENaC) subunits. Expression of truncated β and γ hENaC subunits increased Na + current. However, truncation did not alter single-channel conductance or open state probability, suggesting there were more channels in the plasma membrane. Moreover, truncation of the C-terminus of the β subunit increased apical cell-surface expression of hENaC in a renal epithelium. We identified a conserved motif in the C-terminus of all three subunits that, when mutated, reproduced the effect of Liddle's truncations. Further, both truncation of the C-terminus and mutation of the conserved C-terminal motif increased surface expression of chimeric proteins containing the C-terminus of β hENaC. Thus, by deleting a conserved motif, Liddle's mutations increase the number of Na + channels in the apical membrane, which increases renal Na + absorption and creates a predisposition to hypertension.
Frédéric Boal - One of the best experts on this subject based on the ideXlab platform.
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The Variable C-Terminus of Cysteine String Proteins Modulates Exocytosis and Protein−Protein Interactions†
Biochemistry, 2004Co-Authors: Frédéric Boal, P Scotti, Céline Tessier, Hui Zhang, Jochen LangAbstract:Cysteine string proteins (Csps) are vesicle proteins involved in neurotransmission and hormone exocytosis. They are composed of distinct domains: a variable N-Terminus, a J-domain followed by a linker region, a cysteine-rich string, and a C-terminus which diverges among isoforms. Their precise function and interactions are not fully understood. Using insulin exocytosis as a model, we show that the linker region and the C-terminus, but not the variable N-Terminus, regulate overall secretion. Moreover, endogenous Csp1 binds in a calcium-dependent manner to monomeric VAMP2, and this interaction requires the C-terminus of Csp. The interaction is isoform specific as recombinant Csp1 binds VAMP1 and VAMP7, but not VAMP3. Cross-linking in permeabilized clonal β-cells revealed homodimerization of Csp which is stimulated by Ca2+ and again modulated by the variant C-terminus. Our data suggest that both interactions of Csp occur during exocytosis and may explain the effect of the variant C-terminus of this chaperon...
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The variable C-terminus of cysteine string proteins modulates exocytosis and protein-protein interactions.
Biochemistry, 2004Co-Authors: Frédéric Boal, P Scotti, Céline Tessier, Hui Zhang, Jochen LangAbstract:Cysteine string proteins (Csps) are vesicle proteins involved in neurotransmission and hormone exocytosis. They are composed of distinct domains: a variable N-Terminus, a J-domain followed by a linker region, a cysteine-rich string, and a C-terminus which diverges among isoforms. Their precise function and interactions are not fully understood. Using insulin exocytosis as a model, we show that the linker region and the C-terminus, but not the variable N-Terminus, regulate overall secretion. Moreover, endogenous Csp1 binds in a calcium-dependent manner to monomeric VAMP2, and this interaction requires the C-terminus of Csp. The interaction is isoform specific as recombinant Csp1 binds VAMP1 and VAMP7, but not VAMP3. Cross-linking in permeabilized clonal β-cells revealed homodimerization of Csp which is stimulated by Ca2+ and again modulated by the variant C-terminus. Our data suggest that both interactions of Csp occur during exocytosis and may explain the effect of the variant C-terminus of this chaperon...
Alan L. Sallman - One of the best experts on this subject based on the ideXlab platform.
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Exercise increases the circulating concentration of the N-Terminus of the atrial natriuretic factor prohormone in normal individuals.
American heart journal, 1991Co-Authors: Bonnie J. Baker, Chris J. Winters, Ha Dinh, Richard P. Wyeth, Alan L. SallmanAbstract:Recently two peptides consisting of amino acids (aa) 1 to 30 and 31 to 67 of the N-Terminus of the 126 aa prohormone of atrial natriuretic factor (proANF), as well as atrial natriuretic factor (ANF, aa 99 to 126; C-terminus), were found to have vasodilatory and natriuretic properties. These peptides, as well as ANF, circulate in humans as part of the N-Terminus of the prohormone. To determine the effect of graded exercise on the circulating concentrations of the N-Terminus and C-terminus of the ANF prohormone in normal persons, 12 healthy individuals (mean age 45 ± 2 years) were evaluated before, for 2 hours after, and during bicycle exercise at a work loads of 25, 50, 75, 100, 125, 150, and 175 W. Both the N- and C-terminus of the ANF prohormone were released simultaneously with graded exercise in direct proportion to the intensity of the work load, measured objectively via maximal oxygen consumption (VO2max), respiratory quotient, and heart rate. Both the N-Terminus and C-terminus of the ANF prohormone had strong positive correlations (p < 0.001) with blood pressure, heart rate, VO2max, and respiratory quotient. Following exercise, the C-terminus returned to preexercise levels within 30 minutes, while the N-Terminus remained significantly elevated at 30 and 60 minutes postexercise, reflecting the longer half-life of the N-Terminus in the circulation.
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increased release of the n terminal and c terminal portions of the atrial natriuretic factor prohormone during immersion induced central hypervolemia in cirrhotic humans
American Journal of Nephrology, 1991Co-Authors: David L Vesely, Chris J. Winters, Alan L. Sallman, David M Rico, Richard A Preston, Murray EpsteinAbstract:The role of peptides from the N-Terminus and C-terminus of the 126 amino acid (a.a.) atrial natriuretic factors (ANF) prohormone in modulating renal sodium and water handling in cirrhotic patients has
