Inhibition of Enzymes and Secretory Transport

2006 ◽  
pp. 100-125
Keyword(s):  
Secretory Transport

scholarly journals Ceramide chain length–dependent protein sorting into selective endoplasmic reticulum exit sites

2020 ◽  
Vol 6 (50) ◽  
pp. eaba8237
Author(s):  
Sofia Rodriguez-Gallardo ◽  
Kazuo Kurokawa ◽  
Susana Sabido-Bozo ◽  
Alejandro Cortes-Gomez ◽  
Atsuko Ikeda ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Chain Length ◽  
Secretory Pathway ◽  
Protein Sorting ◽  
Endoplasmic Reticulum Membrane ◽  
Lipid Chain ◽  
Secretory Transport ◽  
Dependent Protein ◽  
Cellular Compartmentalization

Protein sorting in the secretory pathway is crucial to maintain cellular compartmentalization and homeostasis. In addition to coat-mediated sorting, the role of lipids in driving protein sorting during secretory transport is a longstanding fundamental question that still remains unanswered. Here, we conduct 3D simultaneous multicolor high-resolution live imaging to demonstrate in vivo that newly synthesized glycosylphosphatidylinositol-anchored proteins having a very long chain ceramide lipid moiety are clustered and sorted into specialized endoplasmic reticulum exit sites that are distinct from those used by transmembrane proteins. Furthermore, we show that the chain length of ceramide in the endoplasmic reticulum membrane is critical for this sorting selectivity. Our study provides the first direct in vivo evidence for lipid chain length–based protein cargo sorting into selective export sites of the secretory pathway.

scholarly journals Cytochemical localization of calcium and Ca2+,Mg2(+)-adenosine triphosphatase in colchicine-altered rat incisor ameloblasts.

1990 ◽  
Vol 38 (10) ◽  
pp. 1469-1478 ◽  
Author(s):  
D R Eisenmann ◽  
A H Salama ◽  
A M Zaki ◽  
S H Ashrafi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Adenosine Triphosphatase ◽  
Morphological Changes ◽  
Rat Incisor ◽  
Cytochemical Localization ◽  
Early Maturation ◽  
Transmission Electron ◽  
Maturation Stages ◽  
Secretory Transport

Colchicine is known to affect secretory, transport, and degradative functions of ameloblasts. The effects of colchicine on membrane-associated calcium and Ca2+,Mg2(+)-ATPase in secretory and maturation ameloblasts were investigated cytochemically. The pyroantimonate (PPA) method was used for localizing calcium and a modified Wachstein-Meisel medium was used to localize Ca2+,Mg2(+)-ATPase. Sections representing secretory and early maturation stages were examined by transmission electron microscopy. Morphological changes induced by colchicine included dislocated organelles and other well-established reactions to such anti-microtubule drugs. Calcium pyroantimonate (Ca-PA) deposits in most ameloblast types were markedly reduced, with the greater reduction occurring in those cells more severely altered morphologically. However, the cell membranes of both control and experimental smooth-ended maturation ameloblasts were essentially devoid of Ca-PA. The normal distribution and intensity of Ca2+,Mg2(+)-ATPase was not affected by colchicine. Because the observed reduction of membrane-associated calcium is apparently not mediated by Ca2+,Mg2(+)-ATPase in this case, other aspects of the calcium regulating system of ameloblasts are apparently targeted by colchicine.

Interactions between endocytosis and secretory transport

2009 ◽  
pp. 475-484
Author(s):  
Galina V. Beznoussenko ◽  
Margit Pavelka ◽  
Alexander A. Mironov
Keyword(s):  
Secretory Transport

Coupled transport of p-aminohippurate by rat kidney basolateral membrane vesicles

1988 ◽  
Vol 255 (4) ◽  
pp. F597-F604 ◽  
Author(s):  
J. B. Pritchard
Keyword(s):  
Rat Kidney ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Coupled System ◽  
Disulfonic Acid ◽  
Coupled Transport ◽  
Indirect Coupling ◽  
Negative Membrane Potential ◽  
Secretory Transport ◽  
Apical Membranes

p-Aminohippuric acid (PAH) transport by basolateral membrane (BLM) vesicles isolated from rat renal cortex was stimulated very little by a Na+ gradient (out greater than in). However, when micromolar concentrations of glutaric acid or alpha-ketoglutaric acid were added in the presence of a out greater than in Na+ gradient, PAH uptake was accelerated greater than 20-fold and an overshoot of greater than fivefold was produced. Other anions, e.g., fumarate, stimulated PAH uptake very modestly under these conditions (approximately 2-fold), and that stimulation was totally prevented by short circuiting, i.e., with K+ (in = out) and valinomycin. Glutarate-stimulated uptake was inhibited by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) and probenecid and was slightly stimulated by the imposition of an inside-negative membrane potential. Furthermore, even in the absence of a Na+ gradient, glutarate-loaded vesicles exhibited a marked acceleration of PAH uptake (5-fold) and a modest overshoot (2.5-fold). These results suggest an indirect coupling of BLM PAH uptake to the Na+ gradient by a cyclic accumulation (Na+-dependent) of glutarate followed by its efflux from the vesicle in exchange for PAH. This coupled system was absent in apical membranes. Thus net secretory transport of PAH may entail Na+-dependent, glutarate-driven PAH uptake at the BLM, followed by the exit of PAH into the lumen down its electrochemical gradient, probably in exchange for other anions, e.g., Cl-, HCO3-, or OH-.

Organic cation secretion by Cancer borealis urinary bladder

1987 ◽  
Vol 252 (1) ◽  
pp. R153-R159 ◽  
Author(s):  
D. S. Miller ◽  
C. W. Holliday
Keyword(s):  
Polyethylene Glycol ◽  
Urinary Bladder ◽  
Secretory Pathway ◽  
Organic Cation ◽  
Homarus Americanus ◽  
Cancer Borealis ◽  
Cancer Irroratus ◽  
Clearance Studies ◽  
Secretory Transport ◽  
Initial Clearance

In the crab, Cancer borealis, initial clearance studies showed a potent renal excretory system for the model organic cation, tetraethylammonium (TEA). TEA clearance averaged 145 +/- 32 ml/day, which was 18 times the paired polyethylene glycol clearance. TEA uptake by slices of urinary bladder was concentrative, saturable, inhibitable by N1-methylnicotinamide chloride, and dependent on glycolytic, but not oxidative, metabolism. When mounted in flux chambers, bladders exhibited a large net secretory flux. For 0.1 mM TEA, the ratio of secretory to reabsorptive fluxes was 65. Urinary bladders from another crab, Cancer irroratus, and a lobster, Homarus americanus, also exhibited net TEA secretion. In C. borealis bladder, secretory transport was concentrative, saturable, and nearly abolished by addition of 1 mM quinine to the serosal bath. Reabsorptive transport was not concentrative and was not reduced by luminal quinine. The data are consistent with a secretory pathway that is transcellular and mediated by carriers at both the serosal and luminal membranes.

Secretion of tetraethylammonium by proximal tubules of rabbit kidneys

1983 ◽  
Vol 245 (2) ◽  
pp. F238-F246 ◽  
Author(s):  
C. Schali ◽  
L. Schild ◽  
J. Overney ◽  
F. Roch-Ramel
Keyword(s):  
Membrane Permeability ◽  
Cellular Uptake ◽  
Incubation Medium ◽  
Proximal Tubules ◽  
Tissue Water ◽  
Secretory Rate ◽  
Luminal Membrane ◽  
Secretory Transport ◽  
Energy Dependent

The secretory transport of tetraethylammonium (TEA) was investigated in perfused and nonperfused isolated S1, S2, and S3 segments of proximal tubules from rabbit kidneys. In the perfused tubules the transepithelial net secretory flux and in nonperfused tubules the TEA cellular uptake were saturable (Km = 67 microM, Vmax = 2,480 fmol X min-1 X mm-1 in perfused S2 segments), energy dependent, and inhibited by mepiperphenidol. The net secretory flux of TEA (J b leads to j TEA) at a bath TEA concentration of 40 microM differed for the three segments and decreased in the order S1 greater than S2 greater than S3. The concentration of TEA in the perfusate leaving the tubule was approximately twice as great and the intracellular TEA concentration approximately 40 times as great as that in the bath. In nonperfused segments (40 microM TEA in the incubation medium) the TEA tissue water-to-medium ratio reached 100. In the three segments the ability to accumulate TEA across the peritubular membrane, thus, was similar, but the transepithelial secretory flux differed significantly. The differences in secretory rate between the three segments presumably result from differences in the luminal membrane permeability.

scholarly journals Regulation of intracellular membrane trafficking and cell dynamics by syntaxin-6

2012 ◽  
Vol 32 (4) ◽  
pp. 383-391 ◽  
Author(s):  
Jae-Joon Jung ◽  
Shivangi M. Inamdar ◽  
Ajit Tiwari ◽  
Amit Choudhury
Keyword(s):  
Membrane Trafficking ◽  
Critical Role ◽  
Cell Types ◽  
Intracellular Membrane ◽  
Cellular Functions ◽  
Cell Dynamics ◽  
Transport Pathways ◽  
Protein Receptor ◽  
Secretory Transport ◽  
Target Membrane

Intracellular membrane trafficking along endocytic and secretory transport pathways plays a critical role in diverse cellular functions including both developmental and pathological processes. Briefly, proteins and lipids destined for transport to distinct locations are collectively assembled into vesicles and delivered to their target site by vesicular fusion. SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) proteins are required for these events, during which v-SNAREs (vesicle SNAREs) interact with t-SNAREs (target SNAREs) to allow transfer of cargo from donor vesicle to target membrane. Recently, the t-SNARE family member, syntaxin-6, has been shown to play an important role in the transport of proteins that are key to diverse cellular dynamic processes. In this paper, we briefly discuss the specific role of SNAREs in various mammalian cell types and comprehensively review the various roles of the Golgi- and endosome-localized t-SNARE, syntaxin-6, in membrane trafficking during physiological as well as pathological conditions.

scholarly journals Digoxin net secretory transport in bronchial epithelial cell layers is not exclusively mediated by P-glycoprotein/MDR1

2014 ◽  
Vol 86 (1) ◽  
pp. 74-82 ◽  
Author(s):  
Victoria Hutter ◽  
David Y.S. Chau ◽  
Constanze Hilgendorf ◽  
Alan Brown ◽  
Anne Cooper ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Bronchial Epithelial Cell ◽  
Bronchial Epithelial ◽  
P Glycoprotein ◽  
Cell Layers ◽  
Secretory Transport
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