title: Activation of protein-tyrosine kinase p72syk with concanavalin A in polymorphonuclear neutrophils.
abstract: We studied the abundance, subcellular distribution of a non-receptor protein-tyrosine kinase p72syk (Taniguchi, T., Kobayashi, T., Kondo, J., Takahashi, K., Nakamura, H., Suzuki, J., Nagai, K., Yamada, T., Nakamura, S., and Yamamura, H. (1991) J. Biol. Chem. 266, 15790-15796) in porcine polymorphonuclear neutrophils and the activation upon the stimulation with concanavalin A. The abundance was about 0.1% of total proteins and mainly distributed in the particulate fraction. Upon concanavalin A stimulation, the activity of p72syk increased within 30 s, attained to the maximum level at 1 min, and then returned to the basal level within 6 min. This activation was observed in a dose-dependent manner and abrogated by simultaneous addition of methyl alpha-mannopyranoside. When both extra- and intracellular Ca2+ were depleted, the activation of p72syk was still persistent; in contrast, the deactivation process was completely abrogated even at 6 min after stimulation. The replenishment of Ca2+ in the presence of A23187 resulted in a similar deactivation pattern as seen in the Ca(2+)-rich condition. In addition, genistein and herbimycin A, potent protein-tyrosine-kinase inhibitors, were capable of reducing concanavalin A-evoked p72syk activation and Ca2+ mobilization as well as the aggregation and lysozyme release. Furthermore, A23187-induced Ca2+ accumulation in inhibitor-treated cells resulted in the restoration of those cellular responses. These lines of evidence suggest that p72syk is activated with concanavalin A in a Ca(2+)-independent manner, participating in a mechanism of Ca2+ recruitment, and negatively regulated by a feedback mechanism through Ca2+ in neutrophils.
authors.affiliation: Department of Biochemistry, Fukui Medical School, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Asahi
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.forename: E
authors.initials: E
authors.lastname: Hashimoto
authors.forename: T
authors.initials: T
authors.lastname: Inazu
authors.forename: H
authors.initials: H
authors.lastname: Maeda
authors.forename: H
authors.initials: H
authors.lastname: Yamamura
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002451:Cell Compartmentation; D003208:Concanavalin A / Q000494:pharmacology; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism*; D019833:Genistein; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D007529:Isoflavones / Q000494:pharmacology; D009504:Neutrophils / Q000201:enzymology*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D013552:Swine; D000072377:Syk Kinase
chemical_list: D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D007529:Isoflavones; D003208:Concanavalin A; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D000072377:Syk Kinase; D002118:Calcium