Post-Golgi trafficking of rice storage proteins requires the small GTPase Rab7 activation complex MON1-CCZ1.

Protein storage vacuoles (PSVs) are unique organelles that accumulate storage proteins in plant seeds. Although morphological evidence points to the existence of multiple PSV-trafficking pathways for storage protein targeting, the molecular mechanisms that regulate these processes remain mostly unknown. Here, we report the functional characterization of the rice (Oryza sativa) glutelin precursor accumulation7 (gpa7) mutant, which over-accumulates 57-kDa glutelin precursors in dry seeds. Cytological and immunocytochemistry studies revealed that the gpa7 mutant exhibits abnormal accumulation of storage prevacuolar compartment-like structures, accompanied by the partial mistargeting of glutelins to the extracellular space. The gpa7 mutant was altered in the CCZ1 locus, which encodes the rice homolog of Arabidopsis (Arabidopsis thaliana) CALCIUM CAFFEINE ZINC SENSITIVITY1a (CCZ1a) and CCZ1b. Biochemical evidence showed that rice CCZ1 interacts with MONENSIN SENSITIVITY1 (MON1) and that these proteins function together as the Rat brain 5 (Rab5) effector and the Rab7 guanine nucleotide exchange factor (GEF). Notably, loss of CCZ1 function promoted the endosomal localization of vacuolar protein sorting-associated protein 9 (VPS9), which is the GEF for Rab5 in plants. Together, our results indicate that the MON1-CCZ1 complex is involved in post-Golgi trafficking of rice storage protein through a Rab5- and Rab7-dependent pathway.

Enantioselective Synthesis of 3-Substituted 3-Amino-2-oxindoles by Amination with Anilines.

A chiral N,N'-dioxide-nickel(II) complex-catalyzed asymmetric amination of 3-bromo-3-substituted oxindoles with anilines has been developed. A series of alkyl or aryl 3-amino-indolinones with quaternary stereocenters were obtained in high yields with excellent ee values in one step (up to 99 % yield, up to 96 % ee). The method provided a ready route to optically active intermediates of 3-amino-2-oxindole-based bioactive compounds. Moreover, a possible transition-state model is proposed so as to elucidate the origin of the chirality based on the X-ray crystal structure of the catalyst and the adduct.

Asymmetric Catalytic [2,3]†Stevens and Sommelet-Hauser Rearrangements of α-Diazo Pyrazoleamides with Sulfides.

Catalytic enantioselective [2,3] Stevens and Sommelet-Hauser rearrangements of α-diazo pyrazoleamides with sulfides were achieved by utilizing chiral N,N'-dioxide/nickel(II ) complex catalysts. These rearrangements proceeded well under mild reaction conditions, providing rapid and facile access to a series of functionalized 1,6-dicarbonyls or sulfane-substituted phenylacetates with high to excellent enantioselectivities. The catalytic system shows excellent stereocontrol, discriminating between the heterotopic lone pairs of sulfur and controlling both the 1,3-proton transfer and the [2,3]-σ rearrangement.

COMP Improves Ang-II-Induced Atrial Fibrillation via TGF-ß Signaling Pathway.

Cartilage oligomeric matrix protein (COMP) regulates transforming growth factor-ß (TGF-ß) signaling pathway, which has been proved to be associated with skin fibrosis and pulmonary fibrosis. Atrial fibrosis is a major factor of atrial fibrillation (AF). Nevertheless, the interaction between COMP and TGF-ß as well as their role in AF remains undefined. The purpose of this study is to clarify the role of COMP in AF and explore its potential mechanism. The hub gene of AF was identified from two datasets using bioinformatics. Furthermore, it was verified by the downregulation of COMP in angiotensin-II (Ang-II)-induced AF in mice. Moreover, the effect on AF was examined using CCK8 assay, ELISA, and western blot. The involvement of TGF-ß pathway was further discussed. The expression of COMP was the most significant among all these hub genes. Our experimental results revealed that the protein levels of TGF-ß1, phosphorylated Smad2 (P-Smad2), and phosphorylated Smad3 (P-Smad3) were decreased after silencing COMP, which indicated that COMP knockdown could inhibit the activation of TGF-ß pathway in AF cells. However, the phenomenon was reversed when the activator SRI was added. COMP acts as a major factor and can improve Ang-II-induced AF via TGF-ß signaling pathway. Thus, our research enriches the understanding of the interaction between COMP and TGF-ß in AF, and provides reference for the pathogenesis and diagnosis of AF.

Secondary amines as coupling partners in direct catalytic asymmetric reductive amination.

The secondary amine participating asymmetric reductive amination remains an unsolved problem in organic synthesis. Here we show for the first time that secondary amines are capable of effectively serving as N-sources in direct asymmetric reductive amination to afford corresponding tertiary chiral amines with the help of a selected additive set under mild conditions (0-25 °C). The applied chiral phosphoramidite ligands are readily prepared from BINOL and easily modified. Compared with common tertiary chiral amine synthetic methods, this procedure is much more concise and scalable, as exemplified by the facile synthesis of rivastigmine and N-methyl-1-phenylethanamine.