Ionotropic glutamate receptors (iGluRs) are ligand-gated cation channels that mediate fast excitatory neurotransmission in the mammalian central nervous system. In the model plant Arabidopsis thaliana, a family of 20 glutamate receptor-like proteins (GLRs) shares similarities to animal iGluRs in sequence and predicted secondary structure. However, the function of GLRs in plants is little known. In the present study, a serine site (Ser-860) of AtGLR3.7 phosphorylated by a calcium-dependent protein kinase (CDPK) was identified and confirmed by an in vitro kinase assay. Using a bimolecular fluorescence complementation and quartz crystal microbalance analyses, the physical interaction between AtGLR3.7 and the 14-3-3ω protein was confirmed. The mutation of Ser-860 to alanine abolished this interaction, indicating that Ser-860 is the 14-3-3ω binding site of AtGLR3.7. Compared with wild type, seed germination of the glr3.7-2 mutant was more sensitive to salt stress. However, the primary root growth of GLR3.7-S860A overexpression lines was less sensitive to salt stress than that of the wild-type line. In addition, the increase of cytosolic calcium ion concentration by salt stress was significantly lower in the glr3.7-2 mutant line than in the wild-type line. Moreover, association of 14-3-3 proteins to microsomal fractions was less in GLR3.7-S860A overexpression lines than in GLR3.7 overexpression line under 150 mM NaCl salt stress condition. Overall, our results indicated that GLR3.7 is involved in salt stress response in A. thaliana by affecting calcium signaling.

3), bearing an unprecedented fullerodiketimide ligand from 1,4-addition of two benzonitrile molecules to the C 60 cage.One of the most fascinating aspects pertaining to organometallic chemistry concerns the activation of organic substrates at metal centers. 1 Transition-metal clusters have attracted increasing attention because of their activity in reactions involving substrates which are not activated by monometallic species. 2 Recently, the availability of gram quantities of the fullerene C 60 has facilitated the study of the reactivity of this intriguing molecule. 3,4 Subsequent work has been extensive, and many attempts have been made to coordinate fullerenes to metals 5 and to incorporate metal-binding groups into their structures. 6 The syntheses of such compounds offer the capability to exploit the chemical reactivity, photochemical behavior, redox properties, and novel structural features that a fullerene group provides. 7 Investigation of the reactivity of fullerene-bound organometallic compounds has also become an attractive research topic. 8 As part of our continuing interest in metal−fullerene chemistry, 9 herein we report a novel reaction involving concomitant activation of C 60 and benzonitrile molecules mediated by triosmium clusters. ■ RESULTS AND DISCUSSIONOs 3 (CO) 12 (or Os 3 (CO) 10 (NCPh) 2 ) and 2 equiv of C 60 in benzonitrile/o-dichlorobenzene solution were heated to reflux for 3 h under a dinitrogen atmosphere. After purification of the products by TLC (silica gel), three cluster complexes were isolated, characterized as Os 3 (CO) 9 (μ 3 ,