title: Stress-induced tyrosine phosphorylation of actin in Dictyostelium cells and localization of the phosphorylation site to tyrosine-53 adjacent to the DNase I binding loop.
abstract: Actin is known to be phosphorylated at tyrosine, serine, or threonine residues in various cells. In cells of Dictyostelium discoideum, a rise in the tyrosine phosphorylation of actin is observed in response to ATP depletion. An actin fraction rich in phosphotyrosine was obtained by chromatography on the weak anion exchanger Mono-P. Mass spectrometry and amino acid sequencing of protease cleavage products indicated that a single tyrosine residue was phosphorylated. Localization of this residue to position 53 of the actin sequence attributed the modification to a site that is critical for the capability of actin to polymerize. Induction of the tyrosine phosphorylation by heat shock and Cd2+ ions indicates that this modification of actin is implicated in the response of Dictyostelium cells to stress.
mesh_terms: D000199:Actins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001386:Azides / Q000494:pharmacology*; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003850:Deoxyribonuclease I / Q000378:metabolism*; D004023:Dictyostelium / Q000187:drug effects / Q000378:metabolism*; D006358:Hot Temperature; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000032:analysis; D019810:Sodium Azide; D013312:Stress, Physiological; D014443:Tyrosine
chemical_list: D000199:Actins; D001386:Azides; D010446:Peptide Fragments; D019000:Phosphotyrosine; D014443:Tyrosine; D000255:Adenosine Triphosphate; D019810:Sodium Azide; D003850:Deoxyribonuclease I