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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
13
pubmed:dateCreated
2005-3-28
pubmed:abstractText
Receptor-coupled [Ca2+]i increase is initiated in the apical region of epithelial cells and has been associated with apically localized Ca2+-signaling proteins. However, localization of Ca2+ channels that are regulated by such Ca2+-signaling events has not yet been established. This study examines the localization of TRPC channels in polarized epithelial cells and demonstrates a role for TRPC3 in apical Ca2+ uptake. Endogenously and exogenously expressed TRPC3 was localized apically in polarized Madin-Darby canine kidney cells (MDCK) and salivary gland epithelial cells. In contrast, TRPC1 was localized basolaterally, whereas TRPC6 was detected in both locations. Localization of Galpha(q/11), inositol 1,4,5-trisphosphate receptor-3, and phospholipase Cbeta1 and -beta2 was also predominantly apical. TRPC3 co-immunoprecipitated with endogenous TRPC6, phospholipase Cbetas, Galpha(q/11), inositol 1,4,5-trisphosphate receptor-3, and syntaxin 3 but not with TRPC1. Furthermore, 1-oleoyl-2-acetyl-sn-glycerol (OAG)-stimulated apical 45Ca2+ uptake was higher in TRPC3-MDCK cells compared with control (MDCK) cells. Bradykinin-stimulated apical 45Ca2+ uptake and transepithelial 45Ca2+ flux were also higher in TRPC3-expressing cells. Consistent with this, OAG induced [Ca2+]i increase in the apical, but not basal, region of TRPC3-MDCK cells that was blocked by EGTA addition to the apical medium. Most importantly, (i) TRPC3 was detected in the apical region of rat submandibular gland ducts, whereas TRPC6 was present in apical as well as basolateral regions of ducts and acini; and (ii) OAG stimulated Ca2+ influx into dispersed ductal cells. These data demonstrate functional localization of TRPC3/TRPC6 channels in the apical region of polarized epithelial cells. In salivary gland ducts this could contribute to the regulation of salivary [Ca2+] and secretion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12908-16
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:15623527-Animals, pubmed-meshheading:15623527-Bradykinin, pubmed-meshheading:15623527-Calcium, pubmed-meshheading:15623527-Cell Line, pubmed-meshheading:15623527-Cell Membrane, pubmed-meshheading:15623527-Dogs, pubmed-meshheading:15623527-Electric Impedance, pubmed-meshheading:15623527-Epithelial Cells, pubmed-meshheading:15623527-Immunoblotting, pubmed-meshheading:15623527-Immunohistochemistry, pubmed-meshheading:15623527-Immunoprecipitation, pubmed-meshheading:15623527-Ion Channels, pubmed-meshheading:15623527-Isoenzymes, pubmed-meshheading:15623527-Male, pubmed-meshheading:15623527-Membrane Proteins, pubmed-meshheading:15623527-Microscopy, Confocal, pubmed-meshheading:15623527-Microscopy, Fluorescence, pubmed-meshheading:15623527-Phospholipase C beta, pubmed-meshheading:15623527-Qa-SNARE Proteins, pubmed-meshheading:15623527-Rats, pubmed-meshheading:15623527-Rats, Wistar, pubmed-meshheading:15623527-Salivary Glands, pubmed-meshheading:15623527-Signal Transduction, pubmed-meshheading:15623527-TRPC Cation Channels, pubmed-meshheading:15623527-Type C Phospholipases
pubmed:year
2005
pubmed:articleTitle
Apical localization of a functional TRPC3/TRPC6-Ca2+-signaling complex in polarized epithelial cells. Role in apical Ca2+ influx.
pubmed:affiliation
Secretory Physiology Section, Gene Therapy and Therapeutics Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA.
pubmed:publicationType
Journal Article