Intracellular and transcellular transport of secretory and membrane proteins in the rat hepatocyte
The intra- and transcellular transport of hepatic secretory and membrane proteins was studied in rats in vivo using (/sup 3/H)fucose and (/sup 35/S)cyteine as metabolic precursors. Incorporated radioactivity in plasma, bile, and liver subcellular fractions was measured and the labeled proteins of the Golgi complex, bile and plasma were separated by SDS-PAGE and identified by fluorography. /sup 3/H-radioactivity in Golgi fractions peaked at 10 min post injection (p.i.) and then declined concomitantly with the appearance of labeled glycoproteins in plasma. Maximal secretion of secretory fucoproteins from the Golgi complex occurred between 10 and 20 min p.i. In contrast, the clearance of labeled proteins from Golgi membrane subfractions occurred past 30 min p.i., indicating that membrane proteins leave the Golgi complex at least 10 min later than the bulk of content proteins. A major 80K form of Secretory Component (SC) was identified in the bile by precipitation with an anti IgA antibody. A comparative study of kinetics of transport of /sup 35/S-labeled SC and /sup 35/S-labeled albumin showed that albumin peaked in bile at approx.45 min p.i., whereas the SC peak occurred at 80 min p.i., suggesting that the transit time differs for plasma and membrane proteins which are delivered to the bile canaliculus (BC).
- Research Organization:
- Yale Univ., New Haven, CT (USA)
- OSTI ID:
- 7108206
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CYSTEINE
DAYS LIVING RADIOISOTOPES
DISTRIBUTION
EVEN-ODD NUCLEI
IN VIVO
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
LIVER CELLS
MAMMALS
MEMBRANE TRANSPORT
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PROTEINS
RADIOISOTOPES
RATS
RODENTS
SOMATIC CELLS
SULFUR 35
SULFUR ISOTOPES
THIOLS
TISSUE DISTRIBUTION
TRITIUM COMPOUNDS
VERTEBRATES