NS4B...

... has 4 transmembrane segments, responsible for conferring the protein's membrane association
... has an N-terminal amphipathic helix that mediates membrane association
... is necessary and sufficient to establish a membrane platform for the replication complex, known as the membranous web
... recruits replication complex proteins to the membranous web
... binds RNA, shown to be essential for viral replication
... is a potential new target for novel anti HCV treatment