PubMed Journals: Biochim Biophys Acta

  Source:		PMID: 8664319

    		Biochim Biophys Acta. 1996 Jun 11;1281(2):205-12.
			Cyclic AMP-dependent protein kinase phosphorylates
			residues in the C-terminal domain of the cardiac
			L-type calcium channel alpha1 subunit.

			Leach RN(1), Brickley K, Norman RI.

			Author Information
			(1) Department of Medicine and Therapeutics,
			University of Leicester, Clinical Sciences
			Building, Leicester Royal Infirmary, UK.

			The molecular basis of the regulation of
			cardiac L-type calcium channel activity
			by cAMP-dependent protein kinase (cA-PK)
			remains unclear. Direct cA-PK-dependent
			phosphorylation of the bovine ventricular
			alpha1 subunit in vitro has been demonstrated
			in microsomal membranes, detergent extracts
			and partially purified (+)-[3H]PN 200-110
			receptor preparations. Two 32P-labeled
			phosphopeptides, derived from cyanogen bromide
			cleavage, of 4.7 and 9.5 kDa were immunoprecipitated
			specifically by site-directed antibodies
			against the rabbit cardiac alpha1 subunit
			amino acid sequences 1602-1616 and 1681-1694,
			respectively, consistent with phosphorylation
			at the cA-PK consensus sites at Ser(1627)
			and Ser(1700). No phosphopeptide products
			consistent with phosphorylation at three
			other C-terminal cA-PK consensus phosphorylation
			sites (Ser(1575), Ser(1848) and Ser(1928))
			were identified using similar procedures
			suggesting that these sites are poor substrates
			for this kinase. Ser(1627) and Ser(1700)
			may represent sites of cA-PK phosphorylation
			involved in the physiological regulation of cardiac
			L-type calcium channel function.

			PMID: 8664319 [Indexed for MEDLINE]

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