PubMed Journals: Biochim Biophys Acta

  Source:		PMID: 8380342

    		Biochim Biophys Acta. 1993 Jan 17;1175(2):193-206.
			Phosphorylation of serine 2843 in ryanodine
			receptor-calcium release channel of skeletal
			muscle by cAMP-, cGMP- and CaM-dependent
			protein kinase.

			Suko J(1), Maurer-Fogy I, Plank B, Bertel
			O, Wyskovsky W, Hohenegger M, Hellmann G.

			Author Information
			(1) Pharmakologisches Institut der Universit├Ąt
			Wien, Vienna, Austria.

			The aim of the present study was to determine
			the phosphorylation of the purified ryanodine
			receptor-calcium release channel (RyR) of
			rabbit skeletal muscle sarcoplasmic reticulum
			by the cAMP-dependent protein kinase (PK-A),
			cGMP-dependent protein kinase (PK-G) and
			Ca(2+)-, CaM-dependent protein kinase (PK-CaM)
			and the localization of phosphorylation
			sites. Phosphorylation was highest with
			PK-A (about 0.9 mol phosphate/mol receptor
			subunit), between one-half to two-thirds
			with PK-G and between one-third and more
			than two-thirds with PK-CaM. Phosphoamino
			acid analysis revealed solely labeled phosphoserine
			with PK-A and PK-G and phosphoserine and
			phosphothreonine with PK-CaM. Reverse-phase
			high-performance liquid chromatography (HPLC)
			of cyanogen bromide/trypsin digests of the
			phosphorylated RyR (purified by gel permeation
			HPLC) and two-dimensional peptide maps revealed
			one major phosphopeptide by PK-A and PK-G
			phosphorylation and several labeled peaks
			by PK-CaM phosphorylation. Automated Edman
			sequence analysis of the major phosphopeptide
			obtained from PK-A and PK-G phosphorylation
			and one phosphopeptide obtained from PK-CaM
			phosphorylation yielded the sequence KISQTAQTYDPR
			(residues 2841-2852) with serine 2843 as
			phosphorylation site (corresponding to the
			consensus sequence RKIS), demonstrating
			that all three protein kinases phosphorylate
			the same serine residue in the center of
			the receptor subunit, a region proposed
			to contain the modulator binding sites of
			the calcium release channel.

			PMID: 8380342 [Indexed for MEDLINE]

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