title: Expression of Ca2+-dependent synaptotagmin isoforms in mouse and rat parotid acinar cells.
abstract: Synaptotagmin is a Ca2+ sensing protein, which triggers a fusion of synaptic vesicles in neuronal transmission. Little is known regarding the expression of Ca2+-dependent synaptotagmin isoforms and their contribution to the release of secretory vesicles in mouse and rat parotid acinar cells. We investigated a type of Ca2+-dependent synaptotagmin and Ca2+ signaling in both rat and mouse parotid acinar cells using RT-PCR, microfluorometry, and amylase assay. Mouse parotid acinar cells exhibited much more sensitive amylase release in response to muscarinic stimulation than did rat parotid acinar cells. However, transient [Ca2+]i increases and Ca2+ influx in response to muscarinic stimulation in both cells were identical, suggesting that the expression or activity of the Ca2+ sensing proteins is different. Seven Ca2+-dependent synaptotagmins, from 1 to 7, were expressed in the mouse parotid acinar cells. However, in the rat parotid acinar cells, only synaptotagmins 1, 3, 4 and 7 were expressed. These results indicate that the expression of Ca2+-dependent synaptotagmins may contribute to the release of secretory vesicles in parotid acinar cells.
authors.affiliation: Department of Oral Biology, Yonsei University College of Dentistry, Seodaemun-gu, Seoul 120-752, Korea.
authors.forename: Hae
authors.initials: H
authors.lastname: Jo
authors.forename: Hae Mi
authors.initials: HM
authors.lastname: Byun
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Min Seuk
authors.initials: MS
authors.lastname: Kim
authors.forename: Seung-Hyeoi
authors.initials: SH
authors.lastname: Kim
authors.forename: Jeong Hee
authors.initials: JH
authors.lastname: Hong
authors.forename: Jeong Taeg
authors.initials: JT
authors.lastname: Seo
authors.forename: Syng-Ill
authors.initials: SI
authors.lastname: Lee
authors.forename: Dong Min
authors.initials: DM
authors.lastname: Shin
authors.forename: Heung-Kyu
authors.initials: HK
authors.lastname: Son
mesh_terms: D000681:Amylases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000502:physiology*; D002217:Carbachol / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology; D051379:Mice; D018721:Muscarinic Agonists / Q000494:pharmacology; D010306:Parotid Gland / Q000166:cytology / Q000378:metabolism*; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D050857:Synaptotagmins / Q000378:metabolism*
chemical_list: D018721:Muscarinic Agonists; D020033:Protein Isoforms; D050857:Synaptotagmins; D002217:Carbachol; D000681:Amylases; D002118:Calcium