Intracellular localisation of SNARE proteins in rat parotid acinar cells: SNARE complexes on the apical plasma membrane.
Intracellular localisation of soluble N-ethylmaleimide-sensitive fusion protein (NSF) attachment protein receptors (SNAREs) is an important factor in clarifying whether SNAREs regulate exocytosis in salivary glands. We investigated intracellular localisation of syntaxins 2, 3 and 4 and SNAP-23, which are thought to be target membrane (t)-SNAREs, in rat parotid gland by Western blotting and immunocytochemistry. Syntaxins 2 and 3 were localised in the apical plasma membrane (APM), and syntaxin 4 was localised in the plasma membrane. SNAP-23 was localised in the APM and intracellular membrane (ICM). In a yeast two-hybrid assay, syntaxins 2, 3 and 4 interacted with SNAP-23 and VAMP-3. Using immunoprecipitation methods, syntaxins 3 and 4 were seen to interact with VAMP-8 and SNAP-23 at the APM, respectively. SNAP-23 interacted with syntaxin 3, syntaxin 4, VAMP-2, VAMP-3 and VAMP-8. Many SNARE complexes were detected under non-stimulated/basic conditions in the parotid APM. Some of these complexes may have a role in exocytosis from parotid acinar cells.
Imai
Akane
A
Department of Biochemistry, School of Dentistry at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Niigata 951-8580, Japan. imaiak@ngt.ndu.ac.jp
Nashida
Tomoko
T
Yoshie
Sumio
S
Shimomura
Hiromi
H
D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D010306:Parotid Gland / Q000166:cytology / Q000378:metabolism*; D010486:Periapical Tissue / Q000378:metabolism*; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D051381:Rats; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; C100493:SNAP23 protein, human; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins