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Nonstructural Protein |
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NS4b Protein | |
Description | NS4B is a small (248 aa) hydrophobic protein. NS4B is first produced as a peptide of apparent size 30 kDa and is post-translationally modified, in an unknown way, to produce a polypeptide of apparent size 28 kDa in a cell-line dependent manner NS4B proteins of flaviviruses have their N termini located in the ER lumen due to an N-terminal signal peptide not found in NS4B of hepaciviruses, however, the N terminal tail in hepaciviruses is translocated into ER lumen possibly by a post translational process. This shared topology through varying mechanisms suggests a common function of this protein among the family members. While kunjin NS4B translocates to the nucleus in the early stages of infection, dengue NS4B has is an integral trans membrane protein that co-localsies with ER markers. It has been suggested that NS4B may serve to anchor the viral replication complex to cellular membranes. NS4B also acts as an antagonist of the interferon-α/β induced antiviral response via suppression of STAT-1 phosphorylation and nuclear translocation when over expressed. |
Cellular Location | NS4B is an integral trans-membrane protein that resides primarily in cytoplasmic foci originating from the endoplasmic reticulum. Co-localises with ER markers such as PDI and calnexin. |
Synonyms | NS4B, non structural protein 4B |
References (Pubmed) |
2922923 , 12890635 , 12692244 , 16436383 , 14612562 |