Syntaxin 11 (STX11) belongs to the syntaxin family. It interacts with the SNARE proteins SNAP-23 and VAMP. STX11 behaves as an integral membrane protein despite the lack of a traditional transmembrane domain. The detection of STX11 in human cytotoxic lymphocytes suggests that this protein could play a role in the process leading to degranulation of secretory lysosomes.