Activation of dihydropyridine-sensitive parotid salivary gland calcium channels by epidermal growth factor

B. L. Slomiany, Z. Fekete, J. Liu, V. L.N. Murty, A. Slomiany

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The calcium channel complex of the parotid was isolated from solubilized acinar-cell membranes by affinity chromatography on wheatgerm agglutinin. The channel, after labelling the calcium antagonist-receptor site with [3H]-PN200-100, was reconstituted into phosphatidylcholine vesicles that exhibited active 45Ca2+ uptake. This uptake was independent of sodium and potassium gradients, indicating its electroneutrality. The channels responded in a dose-dependent manner to the dihydropyridine calcium antagonist, PN200-110, which at 0.4 μM exerted a maximal inhibitory effect of 75% on 45Ca2+ uptake; a 46% enhancement in 45Ca2+ uptake occurred with a specific calcium-channel activator, BAY K8644. On epidermal growth-factor (EGF) binding in the presence of ATP, there was an increase in tyrosine phosphorylation of 55 and 170 kDa calcium-channel proteins. Such phosphorylated channels, after reconstitution into vesicles, displayed a 61% greater 45Ca2+ uptake, indicating the involvement of tyrosine kinase in EGF-dependent activation of the calcium channel. The results point towards the importance of EGF in the regulation of calcium homeostasis in salivary gland.

Original languageEnglish (US)
Pages (from-to)863-868
Number of pages6
JournalArchives of Oral Biology
Volume37
Issue number11
DOIs
StatePublished - Nov 1992

All Science Journal Classification (ASJC) codes

  • Otorhinolaryngology
  • Dentistry(all)
  • Cell Biology

Keywords

  • EGF stimulation
  • acinar cell
  • activity
  • calcium channels
  • parotid salivary gland

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