PubMed Journals: J Biol Chem

  Source:		PMID: 8440735

    		J Biol Chem. 1993 Feb 25;268(6):4530-3.
			Identification of 40 S ribosomal protein
			S6 phosphorylation sites in Swiss mouse
			3T3 fibroblasts stimulated with serum.

			Bandi HR(1), Ferrari S, Krieg J, Meyer HE,
			Thomas G.

			Author Information
			(1) Friedrich Miescher Institute, Basel,

			All of the phosphorylation sites in 40 S
			ribosomal protein S6 derived from serum-stimulated
			Swiss mouse 3T3 cells are found within a
			small cyanogen bromide (CNBr) peptide derived
			from the carboxyl terminus, Lys218-Lys249.
			Further cleavage of the CNBr peptide or
			the intact protein with endoproteinase Lys-C
			(endo Lys-C) generated a single phosphorylated
			peptide, implying that all the sites of
			phosphorylation resided either between Arg231
			and Lys243 or between Arg231 and Lys249
			if cleavage at Lys243 was blocked by phosphorylation
			at a nearby residue. To discern between
			these possibilities and to identify the
			phosphorylation sites, the protein was purified
			from serum-stimulated cells and cleaved
			with endo Lys-C, and the single endo Lys-C
			phosphorylated peptide was isolated and
			sequenced following conversion of all the
			phosphorylated serines to S-ethylcysteine.
			The results show that the phosphorylated
			peptide extends from Arg231 to Lys249 and
			that the sites of phosphorylation in vivo
			are Ser235, Ser240, Ser244, and Ser247.

			PMID: 8440735 [Indexed for MEDLINE]

     			                         Tweet       Print