Role of the Amphipathic Peptide of Semliki Forest Virus Replicase Protein nsP1 in Membrane Association and Virus Replication
| Autor: | Andres Merits, Leevi Kääriäinen, Anne Salonen, Pirjo Spuul, Eija Jokitalo, Tero Ahola |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Recombinant Fusion Proteins
viruses Green Fluorescent Proteins Molecular Sequence Data Immunology RNA-dependent RNA polymerase Alphavirus Viral Nonstructural Proteins Virus Replication Semliki Forest virus Microbiology Cell Line 03 medical and health sciences Cricetinae Virology Animals Humans Point Mutation Amino Acid Sequence Peptide sequence 030304 developmental biology 0303 health sciences Microscopy Confocal biology Point mutation Cell Membrane 030302 biochemistry & molecular biology virus diseases RNA-Dependent RNA Polymerase biology.organism_classification Semliki forest virus Fusion protein Genome Replication and Regulation of Viral Gene Expression 3. Good health Membrane protein Viral replication Biochemistry Insect Science RNA Viral Peptides HeLa Cells |
| Zdroj: | Journal of Virology. 81:872-883 |
| ISSN: | 1098-5514 0022-538X |
| DOI: | 10.1128/jvi.01785-06 |
| Popis: | Semliki Forest virus RNA replication takes place in association with specific cytoplasmic vacuoles, derived from the endosomal apparatus. Of the four virus-encoded replicase proteins, nsP1 serves as the membrane anchor of the replication complex. An amphipathic peptide segment, G 245 STLYTESRKLLRSWHLPSV 264 , has been implicated in the membrane binding of nsP1. nsP1 variants with changes within the peptide were studied after protein expression and in the context of virus infection. Proteins with mutations R253E and W259A accumulated in the cytoplasm and were very poorly palmitoylated. The same mutations also drastically affected the localization of the precursor polyprotein P123, and they were lethal when introduced into the virus genome. Mutations R253A and L255A+L256A partially changed the localization of nsP1, and the respective viruses acquired compensatory changes. L255A+L256A only yielded virus encoding L255A+L256V, indicating the importance of a hydrophobic residue in the central 256 position. When fused to green fluorescent protein, the peptide was required in at least two tandem copies to effect a change in localization, but even then the fusion protein was associated with membranes in a nonspecific manner. Thus, the amphipathic peptide is a crucial element for the membrane association of nsP1 and the replication complex. It provides essential affinity for membranes, and other regions of nsP1 also appear to contribute to the localization of the protein. |
| Databáze: | OpenAIRE |
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