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Modulation of mast-cell activation may provide novel ways to control allergic diseases. Here, we show that protein tyrosine phosphatase epsilon (PTPepsilon; Ptpre) plays key regulatory roles during mast-cell activation mediated by the high-affinity IgE receptor (FcepsilonRI). Bone marrow-derived mast cells (BMMC) from Ptpre(-/-) mice exhibited enhanced FcepsilonRI-induced Ca(2+) mobilization and mitogen-activated protein kinase (MAPK) (JNK and p38) activation, and showed corresponding enhancement of evoked degranulation and cytokine production, but not leukotriene production. Examination of proteins linking tyrosine kinase activation and Ca(2+) mobilization revealed that the absence of PTPepsilon leads to increased phosphorylation of the linker for activation of T cells and SH2 domain-containing leucocyte phosphoproteins of 76 kDa, but not Grb2-associated binder-2 (Gab2). Because Gab2 is considered to be situated downstream of Fyn kinase, we reasoned that Fyn may not be a target of PTPepsilon. In the event, Syk but not Lyn was hyperphosphorylated in PTPepsilon-deficient BMMC. Thus, PTPepsilon most likely exerts its effects at the level of Syk, inhibiting downstream events including phosphorylation of SLP-76 and linker of activated T cells and mobilization of Ca(2+). Consistent with the in vitro data, antigen- and IgE-mediated passive systemic anaphylactic reactions were augmented in Ptpre(-/-) mice. Given that the number of mast cells is unchanged in these mice, this observation most likely reflects alterations of mast cell-autonomous signalling events. These data suggest that PTPepsilon negatively regulates FcepsilonRI-mediated signalling pathways and thus constitutes a novel target for ameliorating allergic conditions.

Inelastic scattering of the neutron-rich nucleus 12 Be on lead and carbon targets has been studied by measuring de-excitation γ rays in coincidence with scattered 12 Be. The strong γ -ray transition from the state at E x =2.68(3) MeV following E1 Coulomb excitation was observed for the lead target, leading to an assignment of J π =1 − for the excited state. The low excitation energy of this intruder 1 − state and the deduced large B (E1;0 g.s. + →1 − ) value of 0.051(13) e 2 fm 2 provide a consistent picture of the N =8 shell melting in 12 Be.

We have performed an experiment of Coulomb excitation of a doubly magic nucleus 56Ni to its first excited 2+ state at 2.7 MeV in inverse kinematics. Radioactive 56Ni particles at an incident energy 70.7 MeV/nucleon with 1500 s−1 was obtained via fragmentation of 58Ni at RIPS facility of RIKEN. The E2 transition probability B(E2) between the 0+ ground state to the first 2+ state was deduced to be 580±70 e2fm4 by a coupled channel analysis assuming Coulomb excitation mechanism. The present result agrees with the value deduced from the 56Ni+p inelastic scattering experiment at GSI.