Die Rolle des Signalpeptids für die Reifung des Lassavirus Glykoproteins
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Philipps-Universität Marburg
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Abstract
The surface glycoprotein of Lassa virus is a
type-1 membrane protein. It is synthesized as precursor preGP-C
and posttranslationally modified with N-glycans. After
proteolytic cleavage of the signal peptide GP-C is processed
into its subunits GP1 and GP2 by the host cell protease
SKI-1/S1P. After computer analysis the signal protein of the
glycoprotein exhibits an unusual lenght. The topic of this work
was the characterization of this signal peptide. 1. First, the
exact length of the signal peptide of 58 amino acid residues
was determined experimentally by N-terminal sequencing of the
GP1-subunit and mutational analysis of the potential signal
peptide cleavage site. 2. Topological studies have shown that
the signal peptide comprises an unusual structure with two
distinct hydrophobic domains. As a result, several models of
the topology of the signal peptide in the ER-membrane are
possible. It was shown in this work that only the N-terminal of
both hydrophobic domains spans the ER-membrane leaving an
extraordinary long tail, including the second hydrophobic
region, ER-luminal. 3. The signal peptide was studied
concerning additonal functions apart from its translocation
function. To do so, the native signal peptide was replaced by
other signal peptides. This replacement abolished the
maturation cleavage of the glycoprotein GP-C into its subunits
GP1 and GP2. Cleavage was restored upon coexpression of the
solitary native signal peptide. Using mutational analysis the
region of the signal peptide which is essential for proteolytic
activation of the glycoprotein was mapped to the ER-luminal
part of the signal peptide. Furthermore, especially the region
between both hydrophobic domains is essential for maturation of
the glycoprotein. Using coprecipitation experiments a direct
interaction between the glycoprotein and its signal peptide was
shown. This interaction is mediated by the GP2 subunit of the
glycoprotein. 4. It was shown in this work that the signal
peptide is a structural component of the Lassa virion.
Furthermore, the incorporation of the signal peptide depends on
incorporation of the glycoprotein. The signal peptide itself is
not transport competent. 5. The signal peptides of the
arenaviral glycoproteins are homologous, the interchangeability
of the signal peptides between arenaviral glycoproteins was
confirmed in this work. The presented data therefore can be
transferred to the signal peptides of other arenaviral
glycoproteins.
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Dates
Created: 2004Issued: 2004-03-04Updated: 2011-08-10
Faculty
Medizin
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
Lassasignalpeptidevirusglycoprotein
DFG-subjects
Glykoprotein , TopologieSignalpeptidLassaVirus
DDC-Numbers
570
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Eichler, Robert (128827467): Die Rolle des Signalpeptids für die Reifung des Lassavirus Glykoproteins. : Philipps-Universität Marburg 2004-03-04. DOI: https://doi.org/10.17192/z2004.0084.
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This item has been published with the following license: In Copyright