SNARE involved in targeting and fusion of ER-derived transport vesicles with the Golgi complex as well as Golgi-derived retrograde transport vesicles with the ER. Interacts with STX17. Component of two distinct SNARE complexes consisting of STX5, GOSR2/BOS1, BET1 and SEC22B or STX18, USE1L, BNIP1/SEC20L and SEC22B. YKT6 can probably replace SEC22B as subunit of either complex (By similarity). Interacts with the COPII Sec23/24 complex composed of SEC23A and SEC24A; recruits SEC22B into COPII-coated vesicles to allow its transport from the endoplasmic reticulum to the Golgi (By similarity). Concentrated most in the intermediate compartment/cis-Golgi network and the cis-Golgi cisternae 1 and 2. Greatly reduced in concentration at the trans end of the Golgi apparatus. Belongs to the synaptobrevin family.