Deletion of the propeptide from human preproapolipoprotein A-II redirects cotranslation processing by signal peptidase
The functions of NH/sub 2/-terminal propeptides are not known. The authors have used apoA-II as a model to study prosegment structure/function relationships. The primary translation product of human apolipoprotein A-II mRNA contains an 18-amino acid signal peptide, a 5-amino acid propeptide, and the mature 77-amino acid plasma protein sequence. Its propeptide was deleted by site-directed mutagenesis of a cloned cDNA. The effects of this mutation on cotranslational translocation and proteolytic processing were assessed using an in vitro transcription/translation/microsomal membrane processing system. Deletion of the propeptide did not affect cotranslational translocation. However, without its propeptide, signal peptidase cleavage was redirected to a different site located between the 2nd and 3rd residues of the mature protein. Since the primary structure of the signal peptide was not altered in the mutant, these results suggest that sequences located downstream from the signal peptidase cleavage site (e.g. in propeptides) may modulate, or participate in defining, the correct site of cotranslational proteolytic processing.
- Research Organization:
- Washington Univ. School of Medicine, St. Louis, MO
- OSTI ID:
- 6846708
- Journal Information:
- J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 261:31; ISSN JBCHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Active site of tripeptidyl peptidase II from human erythrocytes is of the subtilisin type
cDNA sequences of two apolipoproteins from lamprey
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMALS
APOLIPOPROTEINS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BIOSYNTHESIS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHEMISTRY
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
DNA
DOGS
DRUGS
ENZYMES
EVEN-ODD NUCLEI
HYDROLASES
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
LIPIDS
LIPOPROTEINS
LIPOTROPIC FACTORS
MAMMALS
MESSENGER-RNA
METHIONINE
MICROSOMES
MUTATIONS
NONSPECIFIC PEPTIDASES
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOIDS
PEPTIDE HYDROLASES
PEPTIDES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PROTEINS
PROTEOLYSIS
RADIOISOTOPES
RECOMBINANT DNA
RNA
STRUCTURE-ACTIVITY RELATIONSHIPS
SULFUR 35
SULFUR ISOTOPES
SYNTHESIS
TRITIUM COMPOUNDS
VALINE
VERTEBRATES