Fig. 4.

A, Syntaxin 3 is present in retina but not brain. Approximately 5 μg of membrane protein from rat retina (R) and rat brain (B) was separated by SDS-PAGE and immunoblotted with antibodies specific for either syntaxin 1 or syntaxin 3. The positions of size markers are indicated on theleft. B, Syntaxin 3 forms a complex with SNAP-25 and synaptobrevin. Retina extract was immunoprecipitated with either protein G–Sepharose alone (−) or protein G–Sepharose + anti-syntaxin 3 (+), followed by immunoblotting the immunoprecipitated material with antibodies against syntaxin 3, SNAP-25, and synaptobrevin.