Syntaxin that may be involved in targeting and fusion of Golgi-derived retrograde transport vesicles with the ER. Component of a SNARE complex consisting of STX18, USE1L, BNIP1/SEC20L, and SEC22B. RINT1/TIP20L and ZW10 are associated with the complex through interaction with BNIP1/SEC20L. Interacts directly with USE1L and BNIP1/SEC20L (By similarity). Belongs to the syntaxin family.