Contribution of topology determinants of a viral movement protein to its membrane association, intracellular traffic, and viral cell-to-cell movement
| Autor: | Vicente Pallás, Ainhoa Genovés, José Antonio Navarro |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Spot-virus MNSV
Immunology Molecular Sequence Data Plasmodesma Biology Topology Microbiology Protein Structure Secondary symbols.namesake Open Reading Frames Viral Proteins Cell Movement Virology Alfalfa mosaic virus Intercellular movement Amino Acid Sequence Movement protein Transmembrane helices Molecular code Coat protein Microscopy Confocal Endoplasmic reticulum Endoplasmic-reticulum Golgi apparatus Alfalfa mosaic-virus Encoded proteins Transport protein Virus-Cell Interactions Transmembrane domain Protein Transport Membrane protein Insect Science Membrane topology symbols Mutagenesis Site-Directed Water interface region Carmovirus Alpha-helices |
| Zdroj: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia instname Digital.CSIC. Repositorio Institucional del CSIC |
| ISSN: | 1098-5514 |
| Popis: | The p7B movement protein (MP) of Melon necrotic spot virus (MNSV) is a single-pass membrane protein associated with the endoplasmic reticulum (ER), the Golgi apparatus (GA)and plasmodesmata (Pd). Experimental data presented here revealed that the p7B transmembrane domain (TMD) was sufficient to target the green fluorescent protein (GFP) to ER membranes. In addition, the short extramembrane regions of p7B were essential for subsequent ER export and transport to GA and Pd. Microsomal partitioning and bimolecular fluorescence assays supported a type II topology of p7B in planta. Mutations affecting conventional determinants of p7B membrane topology such as TMD secondary structure, overall hydrophobicity profile, the so-called “aromatic belt” and the net charge distribution on either side of the TMD were engineered into infectious RNAs to investigate the relationship between the MP structure and MNSV cell-to-cell movement. Results revealed that: i) the overall hydrophobic profile and the α-helix integrity of the TMD were relevant for virus movement; ii) modification of the net charge balance of the regions flanking both TMD sides drastically reduced cell-to-cell movement; iii) localization of p7B to GA was necessary but not sufficient for virus movement and iv) membrane insertion was essential for p7B function in virus movement. Our results therefore indicate that MNSV cell-to-cell movement requires a sequential transport of p7B from the ER via the GA to Pd, which is modulated by a combination of several signals with different strengths in the extramembrane regions and TMD of the MP. The work in our laboratory has been supported by grant BIO08-03528 from the Spanish granting agency DGICYT and by grant ACOMP 2011-074 from the Generalitat Valenciana. J. A. N. and A. G. are recipients of a postdoctoral contract and a PhD fellowship from the Spanish Ministerio de Ciencia e Innovación. |
| Databáze: | OpenAIRE |
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