title: Structural requirements for transport of preprocecropinA and related presecretory proteins into mammalian microsomes.
abstract: The presecretory protein preprocecropinA (which comprises 64 amino acid residues) as well as a synthetic hybrid between preprocecropinA and dihydrofolate reductase (which comprises 252 amino acid residues) are processed by and transported into mammalian microsomes. Transport of both precursor proteins can take place cotranslationally, i.e. with the aid of ribosome and signal recognition particle, or posttranslationally, i.e. independently of these ribonucleoparticles (RNPs). We investigated the role of the precursor structure with respect to competence for RNP-independent transport by constructing deletion mutants and hybrid proteins. The results demonstrate that the signal peptide is essential for RNP-independent transport. Furthermore, the signal peptide is sufficient for translocation of preprocecropinA derivatives up to 85 amino acid residues in size. However, the conformation of the precursor protein is decisive in the case of larger hybrid proteins.
authors.affiliation: Zentrum Biochemie/Abt. Biochemie II, Universität Göttingen, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Schlenstedt
authors.forename: G H
authors.initials: GH
authors.lastname: Gudmundsson
authors.forename: H G
authors.initials: HG
authors.lastname: Boman
authors.forename: R
authors.initials: R
authors.lastname: Zimmermann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001692:Biological Transport; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D007301:Insect Hormones / Q000235:genetics / Q000378:metabolism*; D019476:Insect Proteins; D008322:Mammals; D008861:Microsomes / Q000378:metabolism*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D021382:Protein Sorting Signals / Q000378:metabolism; D015183:Restriction Mapping; D012270:Ribosomes / Q000378:metabolism; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics / Q000378:metabolism*
chemical_list: C059037:CecA2 protein, Bombyx mori; D007301:Insect Hormones; D019476:Insect Proteins; D009838:Oligodeoxyribonucleotides; D011498:Protein Precursors; D021382:Protein Sorting Signals; C069377:preprocecropin D protein, Hyalophora cecropia; D004247:DNA; D013762:Tetrahydrofolate Dehydrogenase