Determinants of UDP Glucuronosyltransferase Membrane Association and Residency in the Endoplasmic Reticulum

1998 ◽  
Vol 356 (1) ◽  
pp. 77-85 ◽  
Author(s):  
R. Meech ◽  
P.I. Mackenzie
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Association ◽  
Udp Glucuronosyltransferase

scholarly journals Investigation of the Endoplasmic Reticulum Localization of UDP-Glucuronosyltransferase 2B7 with Systematic Deletion Mutants

2019 ◽  
Vol 95 (5) ◽  
pp. 551-562 ◽  
Author(s):  
Yuu Miyauchi ◽  
Sora Kimura ◽  
Akane Kimura ◽  
Ken Kurohara ◽  
Yuko Hirota ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Deletion Mutants ◽  
Udp Glucuronosyltransferase

scholarly journals Mechanism of stimulation of microsomal UDP-glucuronosyltransferase by UDP-N-acetylglucosamine

1995 ◽  
Vol 305 (1) ◽  
pp. 321-328 ◽  
Author(s):  
X Bossuyt ◽  
N Blanckaert
Keyword(s):  
Endoplasmic Reticulum ◽  
Glucuronic Acid ◽  
Carrier System ◽  
Transport Pathways ◽  
Weak Inhibitor ◽  
Cytosolic Side ◽  
In Trans ◽  
Udp Glucuronosyltransferase ◽  
Carrier Systems ◽  
Stimulation Of

We propose the existence in rat liver endoplasmic reticulum (ER) of two asymmetric carrier systems. One system couples UDP-N-acetylglucosamine (UDPGlcNAc) transport to UDP-glucuronic acid (UDPGlcA) transport. When UDPGlcNAc was presented at the cytosolic side of the ER, it then acted as a weak inhibitor of UDPGlcA uptake. By contrast, UDPGlcNAc produced a forceful trans-stimulation of microsomal UDPGlcA uptake when it was present within the lumen of the ER. Likewise, cytosolic UDPGlcA strongly trans-stimulated efflux of intravesicular UDPGlcNAc, whereas cytosolic UDPGlcNAc was ineffective in trans-stimulating efflux of UDPGlcA. A second asymmetric carrier system couples UDPGlcNAc transport to UMP transport. Microsomal UDPGlcNAc influx was markedly stimulated by UMP present inside the microsomes. Such stimulation was only apparent when microsomes had been preincubated and thereby preloaded with UMP, indicating that UMP exerted its effect on UDPGlcNAc uptake by trans-stimulation from the lumenal side of the ER membrane. Contrariwise, extravesicular UMP only minimally trans-stimulated efflux of intramicrosomal UDPGlcNAc. It is widely accepted that UDPGlcNAc acts as a physiological activator of hepatic glucuronidation, but the mechanism of this effect has remained elusive. Based on our findings, we propose a model in which the interaction of two asymmetric transport pathways, i.e. UDPGlcA influx coupled to UDPGlcNAc efflux and UDPGlcNAc influx coupled to UMP efflux, combined with intravesicular metabolism of UDPGlcA, forms a mechanism that leads to stimulation of glucuronidation by UDPGlcNAc.

scholarly journals The stop transfer sequence of the human UDP-glucuronosyltransferase 1A determines localization to the endoplasmic reticulum by both static retention and retrieval mechanisms

FEBS Journal ◽  
2005 ◽  
Vol 272 (4) ◽  
pp. 1063-1071 ◽  
Author(s):  
Lydia Barré ◽  
Jacques Magdalou ◽  
Patrick Netter ◽  
Sylvie Fournel-Gigleux ◽  
Mohamed Ouzzine
Keyword(s):  
Endoplasmic Reticulum ◽  
Udp Glucuronosyltransferase

Cytosolic phospholipase A2-α associates with plasma membrane, endoplasmic reticulum and nuclear membrane in glomerular epithelial cells

2000 ◽  
Vol 353 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Jianhong LIU ◽  
Tomoko TAKANO ◽  
Joan PAPILLON ◽  
Abdelkrim KHADIR ◽  
Andrey V. CYBULSKY
Keyword(s):  
Endoplasmic Reticulum ◽  
Arachidonic Acid ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Phospholipase A2 ◽  
Cytosolic Phospholipase A2 ◽  
Membrane Association ◽  
Cytosolic Phospholipase ◽  
Glomerular Epithelial Cells ◽  
In Cells

Eicosanoids mediate complement-dependent glomerular epithelial injury in experimental membranous nephropathy. The release of arachidonic acid from phospholipids by cytosolic phospholipase A2 (cPLA2) is the rate-limiting step in eicosanoid synthesis. The present study examines the association of cPLA2 with membranes of organelles. Glomerular epithelial cells were disrupted by homogenization in Ca2+-free buffer; organelles were separated by gradient centrifugation. The distribution of cPLA2 and organelles was analysed by immunoblotting with antibodies against cPLA2 and organelle markers, or by enzyme assay. In cells incubated with or without the Ca2+ ionophore ionomycin plus PMA, cPLA2 co-localized with plasma membrane, endoplasmic reticulum and nuclei, but not with mitochondria or Golgi. A greater amount of cPLA2 was associated with membranes in stimulated cells, but membrane-associated cPLA2 was readily detectable under resting conditions. The pattern of association of cPLA2 with membrane in cells treated with antibody and complement was similar to that in cells stimulated with ionomycin plus PMA; however, complement did not enhance the membrane association of cPLA2 protein. To determine the functional role of membrane association of cPLA2, phospholipids were labelled with [3H]arachidonic acid. Cells were then incubated with or without antibody and complement and were fractionated. Complement induced a loss of radioactivity from the plasma membrane, endoplasmic reticulum and nuclei, but not from the mitochondrial fraction. Thus the release of arachidonic acid by cPLA2 is due to the hydrolysis of phospholipids at multiple subcellular membrane sites, including the endoplasmic reticulum, plasma membrane and nucleus.

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