These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Studies suggesting the participation of protein kinase A in 1, 25(OH)2-vitamin D3-dependent protein phosphorylation in cardiac muscle.
    Author: Santillán GE, Boland RL.
    Journal: J Mol Cell Cardiol; 1998 Feb; 30(2):225-33. PubMed ID: 9514999.
    Abstract:
    We have previously established that the secosteroid hormone 1alpha, 25-dihydroxy-vitamin D3 [1,25(OH)2D 3] rapidly stimulates dihydropyridine-sensitive calcium channel-mediated Ca2+ influx in chick cardiac muscle by a non-genomic action which is accompanied by phosphorylation of microsomal proteins. In the present study, we investigated the participation of the cyclic AMP/protein kinase A (PKA) signalling pathway in hormone-induced changes on protein phosphorylation in chick heart tissue. A major increase in the phosphorylation of a microsomal protein of 45 kDa, and, to a lesser extent, of a protein of 70 kDa, was observed after incubation with [gamma-32P]ATP of membranes isolated from heart thin slices (HTS) pretreated for 1-5 min with 1,25(OH)2D3. This effect was dose- and time-dependent, reaching a maximum after 3 min and at the physiological concentrations of 10(-10) and 10(-11) M. 1,25(OH)2D3 steadily increased cellular cAMP levels as a function of the dose (10( -12)-10(-9) M). The specific agonist of PKA, Sp-cAMPS and the PKA catalytic subunit stimulated the phosphorylation of the same membrane proteins as the hormone. The 1alpha,25-dihydroxy-vitamin D3-dependent changes in microsomal protein phosphorylation were diminished by the specific PKA inhibitor, Rp-cAMPS. In addition, the PKA activity ratio (-cAMP/+cAMP) increased 60% above the control after treatment of HTS with 10(-11) M 1,25(OH)2D3. The data obtained clearly indicate that activation of the cAMP/PKA signalling pathway mediates the stimulation of protein phosphorylation by 1alpha, 25-dihydroxy-vitamin D3 in chick cardiac muscle.
    [Abstract] [Full Text] [Related] [New Search]