Membrane and secretory proteins are transported from the Golgi complex to the sinusoidal plasmalemma of hepatocytes by distinct vesicular carriers.
Open Access
- 15 May 1994
- journal article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 125 (4), 733-741
- https://doi.org/10.1083/jcb.125.4.733
Abstract
From rat livers labeled in vivo for 30 min with [35S] cys-met, we have isolated two classes of vesicular carriers operating between the Golgi complex and the basolateral (sinusoidal) plasmalemma. The starting preparation is a Golgi light fraction (GLF) isolated by flotation in a discontinuous sucrose density gradient and processed through immunoisolation on magnetic beads coated with an antibody against the last 11 aa. of the pIgA-R tail. GLF and the ensuing subfractions (bound vs nonbound) were lysed, and the lysates processed through immunoprecipitation with anti-pIgA-R and anti-albumin antibodies followed by radioactivity counting, SDS-PAGE, and fluorography. The recovery of newly synthesized pIgA-R was > 90% and the distribution was 90% vs 10% in the bound vs nonbound subfractions, respectively. Albumin radioactivity was recovered to approximately 80%, with 20% and 80% in bound vs nonbound subfractions, respectively. Other proteins studied were: (a) secretory-apolipoprotein-B, prothrombin, C3 component of the complement, and caeruloplasmin; (b) membrane-transferrin receptor, EGR-receptor, asialoglycoprotein receptor, and the glucose transporter. In all the experiments we have performed, the secretory proteins distributed up to 85% in the nonbound subfraction (large secretory vacuoles), whereas the membrane proteins were segregated up to 95% in the bound subfraction (small vesicular carriers). These results suggest that in hepatocytes, membrane and secretory proteins are transported from the Golgi to the basolateral plasmalemma by separate vesicular carriers as in glandular cells capable of constitutive and regulated secretion.Keywords
This publication has 27 references indexed in Scilit:
- The trans-Golgi network can be dissected structurally and functionally from the cisternae of the Golgi complex by brefeldin A.1992
- Secretion of endogenous and exogenous proteins from polarized MDCK cell monolayers.Proceedings of the National Academy of Sciences, 1986
- Biogenesis of the polymeric IgA receptor in rat hepatocytes. II. Localization of its intracellular forms by cell fractionation studies.The Journal of cell biology, 1985
- Endogenous and exogenous domain markers of the rat hepatocyte plasma membrane.The Journal of cell biology, 1985
- Somatostatin discriminates between the intracellular pathways of secretory and membrane proteins.The Journal of cell biology, 1984
- Hepatic Golgi fractions resolved into membrane and content subfractions.The Journal of cell biology, 1982
- Heterogeneity of lipoprotein particles in hepatic Golgi fractions.The Journal of cell biology, 1982
- Endoplasmic reticulum marker enzymes in Golgi fractions--what does this mean?The Journal of cell biology, 1978
- Intracellular Aspects of the Process of Protein SynthesisScience, 1975
- COLCHICINE-INDUCED INHIBITION OF LIPOPROTEIN AND PROTEIN SECRETION INTO THE SERUM AND LACK OF INTERFERENCE WITH SECRETION OF BILIARY PHOSPHOLIPIDS AND CHOLESTEROL BY RAT LIVER IN VIVOThe Journal of cell biology, 1974