Processing of pulmonary surfactant proteolipid SPL(Phe) in rat lung type II epithelial cells
The adsorption and surface tension-reducing properties of pulmonary surfactant phospholipids are significantly enhanced by the presence of essential 6-14,000 Dalton hydrophobic proteins. The biosynthesis of one of these hydrophobic proteins, SPL(Phe), has been studied in rat lung. SPL(Phe) precursors of 40,000 Daltons, pI approximately 6.4-7.4, were identified by immunoprecipitation of in vitro translated rat lung poly A/sup +/ mRNA. The primary translation products were not immunoprecipitated by normal rabbit serum; further, these proteins were not immunoprecipitated in the presence of excess bovine SPL(Phe) or from in vitro translated rat liver poly A/sup +/ mRNA. Processing of the primary translation products by canine pancreatic microsomal membranes resulted in a 42,000 Dalton protein which was susceptible to endoglycosidase F suggesting the presence of asparagine-linked oligosaccharide. To study the processing of the 40,000 Dalton preprotein to the 6-14,000 Dalton form observed in the airway, pulse chase experiments were performed in primary cultures of rat Type II epithelial cells. Intracellular, endo-F sensitive 40,000-42,000 Dalton proteins were observed immediately following a 15 minute pulse with /sup 35/S-methionine and declined to undetectable levels by 3 hours post-label. 6-14,000 Dalton proteins were first detected at 1 hour post-label in both cells and media suggesting that proteolytic cleavage of the 40-42,000 Dalton preprotein occurred in close proximity to secretion.
- Research Organization:
- Univ. of Cincinnati College of Medicine, OH
- OSTI ID:
- 6278711
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
- Country of Publication:
- United States
- Language:
- English
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CLEAVAGE
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IMMUNE REACTIONS
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MESSENGER-RNA
METHIONINE
MICROSOMES
PANCREAS
RATS
SULFUR 35
TRACER TECHNIQUES
AMINO ACIDS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
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CELL CONSTITUENTS
CRYSTAL STRUCTURE
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DIGESTIVE SYSTEM
DRUGS
ENDOCRINE GLANDS
ESTERS
EVEN-ODD NUCLEI
GLANDS
ISOTOPE APPLICATIONS
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LIPOTROPIC FACTORS
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MEMBRANES
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NUCLEI
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ORGANIC ACIDS
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ORGANIC PHOSPHORUS COMPOUNDS
ORGANIC SULFUR COMPOUNDS
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ORGANS
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SYNTHESIS
TISSUES
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550201* - Biochemistry- Tracer Techniques