scholarly journals Exocyst Is Involved in Cystogenesis and Tubulogenesis and Acts by Modulating Synthesis and Delivery of Basolateral Plasma Membrane and Secretory Proteins

2000 ◽  
Vol 11 (12) ◽  
pp. 4259-4275 ◽  
Author(s):  
Joshua H. Lipschutz ◽  
Wei Guo ◽  
Lucy E. O'Brien ◽  
Yen H. Nguyen ◽  
Peter Novick ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Cell Polarity ◽  
Cyst Formation ◽  
Apical Plasma Membrane ◽  
Secretory Proteins ◽  
Plasma Membrane Protein ◽  
Tubule Formation ◽  
Basolateral Plasma Membrane

Epithelial cyst and tubule formation are critical processes that involve transient, highly choreographed changes in cell polarity. Factors controlling these changes in polarity are largely unknown. One candidate factor is the highly conserved eight-member protein complex called the exocyst. We show that during tubulogenesis in an in vitro model system the exocyst relocalized along growing tubules consistent with changes in cell polarity. In yeast, the exocyst subunit Sec10p is a crucial component linking polarized exocytic vesicles with the rest of the exocyst complex and, ultimately, the plasma membrane. When the exocyst subunit human Sec10 was exogenously expressed in epithelial Madin-Darby canine kidney cells, there was a selective increase in the synthesis and delivery of apical and basolateral secretory proteins and a basolateral plasma membrane protein, but not an apical plasma membrane protein. Overexpression of human Sec10 resulted in more efficient and rapid cyst formation and increased tubule formation upon stimulation with hepatocyte growth factor. We conclude that the exocyst plays a central role in the development of epithelial cysts and tubules.

The transcytotic pathway of an apical plasma membrane protein (B10) in hepatocytes is similar to that of IgA and occurs via a tubular pericentriolar compartment

1996 ◽  
Vol 109 (6) ◽  
pp. 1215-1227 ◽  
Author(s):  
I. Hemery ◽  
A.M. Durand-Schneider ◽  
G. Feldmann ◽  
J.P. Vaerman ◽  
M. Maurice
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Apical Membrane ◽  
Rat Hepatocytes ◽  
Apical Plasma Membrane ◽  
Apical Surface ◽  
Plasma Membrane Protein ◽  
Microtubule Disruption

In hepatocytes, newly synthesized apical plasma membrane proteins are first delivered to the basolateral surface and are supposed to reach the apical surface by transcytosis. The transcytotic pathway of apical membrane proteins and its relationship with other endosomal pathways has not been demonstrated morphologically. We compared the intracellular route of an apical plasma membrane protein, B10, with that of polymeric IgA (pIgA), which is transcytosed, transferrin (Tf) which is recycled, and asialoorosomucoid (ASOR) which is delivered to lysosomes. Ligands and anti-B10 monoclonal IgG were linked to fluorochromes or with peroxidase. The fate of each ligand was followed by confocal and electron microscopy in polarized primary monolayers of rat hepatocytes. When fluorescent anti-B10 IgG and fluorescent pIgA were simultaneously endocytosed for 15–30 minutes, they both uniformly labelled a juxtanuclear compartment. By 30–60 minutes, they reached the bile canaliculi. Tf and ASOR were also routed to the juxtanuclear area, but their fluorescence patterns were more punctate. Microtubule disruption prevented all ligands from reaching the juxtanuclear area. This area corresponded, at least partially, to the localization of the mannose 6-phosphate receptor, an endosomal marker. By electron microscopy, the juxtanuclear compartment was made up of anastomosing tubules connected to vacuoles, and was organized around the centrioles. B10 and pIgA were mainly found in the tubules, whereas ASOR was segregated inside the vacuolar elements and Tf within thinner, recycling tubules. In conclusion, transcytosis of the apical membrane protein B10 occurs inside tubules similar to those carrying pIgA, and involves passage via the pericentriolar area. In the pericentriolar area, the transcytotic tubules appear to maintain connections with other endosomal elements where sorting between recycled and degraded ligands occurs.

Somatostatin and analogs inhibit endogenous synaptic plasma membrane protein phosphorylation in vitro

1983 ◽  
Vol 88 (2-3) ◽  
pp. 185-193 ◽  
Author(s):  
Linda A. Dokas ◽  
Henk Zwiers ◽  
David H. Coy ◽  
Willem Hendrik Gispen
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Protein Phosphorylation ◽  
Synaptic Plasma Membrane ◽  
Plasma Membrane Protein

scholarly journals ABCC6 Is a Basolateral Plasma Membrane Protein

2013 ◽  
Vol 112 (11) ◽  
Author(s):  
Viola Pomozi ◽  
Olivier Le Saux ◽  
Christopher Brampton ◽  
Ailea Apana ◽  
Attila Iliás ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Plasma Membrane Protein ◽  
Basolateral Plasma Membrane

A PHOTORECEPTOR SYSTEM REGULATING in vivo AND in vitro PHOSPHORYLATION OF A PEA PLASMA MEMBRANE PROTEIN

1984 ◽  
Vol 39 (6) ◽  
pp. 773-781
Author(s):  
Timothy W. Short ◽  
Markus Porst ◽  
Winslow R. Brigg
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Plasma Membrane Protein

Expression and compartmentalization of integral plasma membrane proteins by hepatocytes and their progenitors in the rat pancreas

1991 ◽  
Vol 98 (1) ◽  
pp. 45-54
Author(s):  
J.R. Bartles ◽  
M.S. Rao ◽  
L.Q. Zhang ◽  
B.E. Fayos ◽  
C.L. Nehme ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Apical Plasma Membrane ◽  
Specific Marker ◽  
Plasma Membrane Protein ◽  
Plasma Membrane Proteins ◽  
Dipeptidylpeptidase Iv ◽  
Copper Depletion ◽  
Pancreatic Hepatocytes

A combination of Western blotting, Northern blotting and immunofluorescence was used to examine the expression and compartmentalization of plasma membrane proteins by those hepatocyte-like cells that arise in the pancreases of rats subjected to sequential dietary copper depletion and repletion. The pancreatic hepatocytes were found to: (1) express several integral membrane proteins known to be concentrated within the apical, lateral or basolateral domains of the plasma membranes of hepatocytes in liver; and (2) compartmentalize the membrane proteins to equivalent plasma membrane domains, despite the organization of these cells into clusters instead of highly vascularized plates. The apical plasma membrane proteins dipeptidylpeptidase IV and HA 4 were found to line bile canaliculus-like openings between adjacent pancreatic hepatocytes; these openings were shown to be continuous with the pancreatic exocrine duct by India ink infusion. In contrast, the basolateral plasma membrane protein rat hepatic lectin-1 and lateral plasma membrane protein HA 321 were detected elsewhere about the surfaces of the pancreatic hepatocytes: by analogy to their respective localizations on hepatocytes in liver, rat hepatic lectin-1 was concentrated on those surfaces exposed to the pancreatic matrix at the periphery of the hepatocyte clusters (the basal surface equivalent), whereas HA 321 was concentrated on those surfaces exposed to adjacent hepatocytes within the clusters. The hepatocyte plasma membrane proteins were found to be expressed in the pancreas at different times during the copper depletion/repletion protocol: for example, rat hepatic lectin-1 and the bulk of the HA 4 were expressed relatively late in the protocol, only after large numbers of pancreatic hepatocytes had appeared; whereas dipeptidylpeptidase IV was induced greater than 10-fold early in the protocol and proved to be an apical-specific marker for those ductular epithelial cells that are believed to be the progenitors of the pancreatic hepatocytes.

Sign in / Sign up

Export Citation Format

Share Document