Lipid-phase structure in epithelial cell membranes: comparison of renal brush border and basolateral membranes

Biochemistry ◽  
1988 ◽  
Vol 27 (6) ◽  
pp. 2077-2083 ◽  
Author(s):  
Nicholas P. Illsley ◽  
Herbert Y. Lin ◽  
A. S. Verkman
1998 ◽  
Vol 345 (2) ◽  
pp. 229-232 ◽  
Author(s):  
Richard M Edwards ◽  
Walter Trizna ◽  
Elwood J Stack

1989 ◽  
Vol 36 (2) ◽  
pp. 183-193 ◽  
Author(s):  
Christian C. Felder ◽  
Anthony M. McKelvey ◽  
Miriam S. Gitler ◽  
Gilbert M. Eisner ◽  
Pedro A. Jose

1983 ◽  
Vol 245 (2) ◽  
pp. F227-F231 ◽  
Author(s):  
C. Le Grimellec ◽  
S. Carriere ◽  
J. Cardinal ◽  
M. C. Giocondi

The physical state of lipids in brush border and basolateral membrane vesicles prepared from normal human kidney cortex was investigated by fluorescence polarization and electron spin resonance. At physiologic temperature, lipids were significantly less ordered, i.e., more fluid, in basolateral than in brush border membranes. This difference was also observed using corresponding liposomes made from total lipid extracts. For both brush border and basolateral membranes, temperature-dependent experiments revealed the existence of a broad thermotropic transition extending approximately from 20 to 42 degrees C. These data are interpreted to indicate that plasma membranes from human kidney cortex function physiologically at the upper critical temperature of a transition that probably corresponds to a liquid crystalline-to-gel lipid phase separation.


1989 ◽  
Vol 257 (5) ◽  
pp. C971-C975 ◽  
Author(s):  
H. A. Skopicki ◽  
K. Fisher ◽  
D. Zikos ◽  
G. Flouret ◽  
D. R. Peterson

These studies were performed to determine if a low-affinity carrier is present in the luminal membrane of proximal tubular cells for the transport of the dipeptide, pyroglutamyl-histidine (pGlu-His). We have previously described the existence of a specific, high-affinity, low-capacity [transport constant (Kt) = 9.3 X 10(-8) M, Vmax = 6.1 X 10(-12) mol.mg-1.min-1] carrier for pGlu-His in renal brush-border membrane vesicles. In the present study, we sought to demonstrate that multiple carriers exist for the transport of a single dipeptide by determining whether a low-affinity carrier also exists for the uptake of pGlu-His. Transport of pGlu-His into brush-border membrane vesicles was saturable over the concentration range of 10(-5)-10(-3) M, yielding a Kt of 6.3 X 10(-5) M and a Vmax of 2.2 X 10(-10) mol.mg-1.min-1. Uptake was inhibited by the dipeptides glycyl-proline, glycyl-sarcosine, and carnosine but not by the tripeptide pyroglutamyl-histidyl-prolinamide. We conclude that 1) pGlu-His is transported across the luminal membrane of the proximal tubule by multiple carriers and 2) the lower affinity carrier, unlike the higher affinity carrier, is nonspecific with respect to other dipeptides.


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