scholarly journals Detection of plasma membrane cholesterol by filipin during microvillogenesis and ciliogenesis in quail oviduct.

1985 ◽  
Vol 33 (1) ◽  
pp. 1-10 ◽  
Author(s):  
B Chailley ◽  
E Boisvieux-Ulrich

Using filipin as a probe for the presence of membrane cholesterol, the evolution of cholesterol distribution in the apical plasma membrane was studied during estrogen-induced ciliogenesis in quail oviduct and compared with the distribution of intramembrane particles (IMPs). Ciliary growth is preceded by the first step of microvillus differentiation. Microvilli emerge in membrane domains rich in IMPs and devoid of filipin-cholesterol (f-c) complexes. However growing microvillus membrane shows f-c complexes. During ciliary growth, microvilli lengthen from 0.5 to 2 microns, indicating that the microvillar membrane is not a membrane reservoir for ciliogenesis. During ciliary growth, the characteristic ciliary necklace IMP rows appear progressively at the base of cilia. The first IMP row is organized in a membrane circlet lacking of f-c complexes, whereas the new shaft membrane in the middle of the circlet exhibits numerous complexes. These two different domains of the cilia keep their specificity during ciliary growth. Only the ciliary tip shows fewer complexes than the shaft membrane. The apical membrane of differentiated ciliated cells is thus composed of various domains, the ciliary shaft full of f-c complexes and poor in IMPs, the ciliary necklace is devoid of f-c complexes and rich in IMPs, the microvilli membrane is rich in both IMPs and f-c complexes, and the interciliary membrane is poor in both f-c complexes and IMPs, whereas the undifferentiated cells exhibit an apical membrane in which f-c complexes and IMPs are distributed homogeneously.

1999 ◽  
Vol 10 (10) ◽  
pp. 3449-3461 ◽  
Author(s):  
Sven C. D. van IJzendoorn ◽  
Dick Hoekstra

In polarized HepG2 cells, the sphingolipids glucosylceramide and sphingomyelin (SM), transported along the reverse transcytotic pathway, are sorted in subapical compartments (SACs), and subsequently targeted to either apical or basolateral plasma membrane domains, respectively. In the present study, evidence is provided that demonstrates that these sphingolipids constitute separate membrane domains at the luminal side of the SAC membrane. Furthermore, as revealed by the use of various modulators of membrane trafficking, such as calmodulin antagonists and dibutyryl-cAMP, it is shown that the fate of these separate sphingolipid domains is regulated by different signals, including those that govern cell polarity development. Thus under conditions that stimulate apical plasma membrane biogenesis, SM is rerouted from a SAC-to-basolateral to a SAC-to-apical pathway. The latter pathway represents the final leg in the transcytotic pathway, followed by the transcytotic pIgR–dIgA protein complex. Interestingly, this pathway is clearly different from the apical recycling pathway followed by glucosylceramide, further indicating that randomization of these pathways, which are both bound for the apical membrane, does not occur. The consequence of the potential coexistence of separate sphingolipid domains within the same compartment in terms of “raft” formation and apical targeting is discussed.


2001 ◽  
Vol 42 (9) ◽  
pp. 1492-1500 ◽  
Author(s):  
Howard S. Kruth ◽  
Ina Ifrim ◽  
Janet Chang ◽  
Lia Addadi ◽  
Daniele Perl-Treves ◽  
...  

2009 ◽  
Vol 33 (10) ◽  
pp. 1079-1086 ◽  
Author(s):  
Nadezhda Stefanova ◽  
Galya Staneva ◽  
Diana Petkova ◽  
Teodora Lupanova ◽  
Roumen Pankov ◽  
...  

1996 ◽  
Vol 109 (6) ◽  
pp. 1215-1227 ◽  
Author(s):  
I. Hemery ◽  
A.M. Durand-Schneider ◽  
G. Feldmann ◽  
J.P. Vaerman ◽  
M. Maurice

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.


2001 ◽  
Vol 114 (7) ◽  
pp. 1331-1341 ◽  
Author(s):  
A.K. Criss ◽  
D.M. Ahlgren ◽  
T.S. Jou ◽  
B.A. McCormick ◽  
J.E. Casanova

The bacterial pathogen Salmonella typhimurium colonizes its animal hosts by inducing its internalization into intestinal epithelial cells. This process requires reorganization of the actin cytoskeleton of the apical plasma membrane into elaborate membrane ruffles that engulf the bacteria. Members of the Ρ family of small GTPases are critical regulators of actin structure, and in nonpolarized cells, the GTPase Cdc42 has been shown to modulate Salmonella entry. Because the actin architecture of epithelial cells is organized differently from that of nonpolarized cells, we examined the role of two ‘Rgr; family GTPases, Cdc42 and Rac1, in invasion of polarized monolayers of MDCK cells by S. typhimurium. Surprisingly, we found that endogenous Rac1, but not Cdc42, was activated during bacterial entry at the apical pole, and that this activation required the bacterial effector protein SopE. Furthermore, expression of dominant inhibitory Rac1 but not Cdc42 significantly inhibited apical internalization of Salmonella, indicating that Rac1 activation is integral to the bacterial entry process. In contrast, during basolateral internalization, both Cdc42 and Rac1 were activated; however, neither GTPase was required for entry. These findings, which differ significantly from previous observations in nonpolarized cells, indicate that the host cell signaling pathways activated by bacterial pathogens may vary with cell type, and in epithelial tissues may further differ between plasma membrane domains.


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