A method has been developed for routine high yield separation of canalicular (cLPM) from basolateral (blLPM) liver plasma membrane vesicles of rat liver. Using a combination of rate zonal floatation (TZ-28 zonal rotor, Sorvall) and high speed centrifugation through discontinuous sucrose gradients, 9-16 mg of cLPM and 15-28 mg of blLPM protein can be isolated in 1 d. cLPM are free of the basolateral markers Na+/K+-ATPase and glucagon-stimulatable adenylate cyclase activities, but are highly enriched with respect to homogenate in the "canalicular marker" enzyme activities leucylnaphthylamidase (48-fold), gamma-glutamyl-transpeptidase (60-fold), 5'-nucleotidase (64-fold), alkaline phosphatase (71-fold), Mg++-ATPase (83-fold), and alkaline phosphodiesterase I (116-fold). In contrast, blLPM are 34-fold enriched in Na+/K+-ATPase activity, exhibit considerable glucagon-stimulatable adenylate cyclase activity, and demonstrate a 4- to 15-fold increase over homogenate in the various "canalicular markers." cLPM have a twofold higher content of sialic acids, cholesterol; and sphingomyelin compared with blLPM. At least three canalicular-(130,000, 100,000, and 58,000 mol wt) and several basolateral-specific protein bands have been detected after SDS PAGE of the two LPM subfractions. Specifically, the immunoglobin A-binding secretory component is restricted to blLPM as demonstrated by immunochemical techniques. These data indicate virtually complete separation of basolateral from canalicular LPM and demonstrate multiple functional and compositional polarity between the two surface domains of hepatocytes.
Skip Nav Destination
Article navigation
1 March 1984
Article|
March 01 1984
Structural and functional polarity of canalicular and basolateral plasma membrane vesicles isolated in high yield from rat liver.
P J Meier
E S Sztul
A Reuben
J L Boyer
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1984) 98 (3): 991–1000.
Citation
P J Meier, E S Sztul, A Reuben, J L Boyer; Structural and functional polarity of canalicular and basolateral plasma membrane vesicles isolated in high yield from rat liver.. J Cell Biol 1 March 1984; 98 (3): 991–1000. doi: https://doi.org/10.1083/jcb.98.3.991
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
Sign in via your Institution
Sign in via your InstitutionSuggested Content
Email alerts
Advertisement
Advertisement