title: VAMP8/endobrevin as a general vesicular SNARE for regulated exocytosis of the exocrine system.
abstract: The molecular mechanism governing the regulated secretion of most exocrine tissues remains elusive, although VAMP8/endobrevin has recently been shown to be the major vesicular SNARE (v-SNARE) of zymogen granules of pancreatic exocrine acinar cells. In this article, we have characterized the role of VAMP8 in the entire exocrine system. Immunohistochemical studies showed that VAMP8 is expressed in all examined exocrine tissues such as salivary glands, lacrimal (tear) glands, sweat glands, sebaceous glands, mammary glands, and the prostate. Severe anomalies were observed in the salivary and lacrimal glands of VAMP8-null mice. Mutant salivary glands accumulated amylase and carbonic anhydrase VI. Electron microscopy revealed an accumulation of secretory granules in the acinar cells of mutant parotid and lacrimal glands. Pilocarpine-stimulated secretion of saliva proteins was compromised in the absence of VAMP8. Protein aggregates were observed in mutant lacrimal glands. VAMP8 may interact with syntaxin 4 and SNAP-23. These results suggest that VAMP8 may act as a v-SNARE for regulated secretion of the entire exocrine system.
authors.affiliation: Institute of Molecular and Cell Biology, Singapore 138673, Singapore.
authors.forename: Cheng-Chun
authors.initials: CC
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Shi
authors.forename: Ke
authors.initials: K
authors.lastname: Guo
authors.forename: Chee Peng
authors.initials: CP
authors.lastname: Ng
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Bin Qi
authors.initials: BQ
authors.lastname: Gan
authors.forename: Hwee
authors.initials: H
authors.lastname: Chien Liew
authors.forename: Jukka
authors.initials: J
authors.lastname: Leinonen
authors.forename: Hannu
authors.initials: H
authors.lastname: Rajaniemi
authors.forename: Zhi Hong
authors.initials: ZH
authors.lastname: Zhou
authors.forename: Qi
authors.initials: Q
authors.lastname: Zeng
authors.forename: Wanjin
authors.initials: W
authors.lastname: Hong
mesh_terms: D000818:Animals; D005088:Exocrine Glands / Q000166:cytology / Q000378:metabolism*; D005089:Exocytosis; D007765:Lacrimal Apparatus / Q000166:cytology / Q000648:ultrastructure; D008297:Male; D051379:Mice; D020836:Protein Structure, Quaternary; D011506:Proteins / Q000737:chemistry; D050683:R-SNARE Proteins / Q000172:deficiency / Q000378:metabolism*; D050600:SNARE Proteins / Q000378:metabolism*; D012469:Salivary Glands / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D022142:Secretory Vesicles / Q000648:ultrastructure
chemical_list: D011506:Proteins; D050683:R-SNARE Proteins; D050600:SNARE Proteins; C491831:Vamp8 protein, mouse