Lewis Liu

A series of derivatives of the known thromboxane A2 prostanoid receptor antagonists, 3-sulfonamido)-5,6,7,8-tetrahydronaphthalen-1-yl)propanoic acid and 3-sulfonamido)ethyl)phenyl) propanoic acid, were synthesized in which the carboxylic acid functional group was replaced with substituted cyclopentane-1,3-dione bioisosteres. Characterization of these molecules led to the discovery of remarkably potent new analogues, some of which were considerably more active than the corresponding parent carboxylic acid compounds. Depending on the choice of the C2 substituent of the CPD unit, these new derivatives can produce either a reversible or an apparent irreversible inhibition of the human TP receptor. Given the potency and the long-lasting inhibition of TP receptor signaling, these novel antagonists may comprise promising leads for the development of antithromboxane therapies.

© 2016 American Society of Plant Biologists. All rights reserved.Calcium/calmodulin-dependent protein kinase has been shown to play an important role in abscisic acid -induced antioxidant defense and enhance the tolerance of plants to drought stress. However, its downstream molecular events are poorly understood. Here, we identify a NAC transcription factor, ZmNAC84, in maize, which physically interacts with ZmCCaMK in vitro and in vivo. ZmNAC84 displays a partially overlapping expression pattern with ZmCCaMK after ABA treatment, and H2O2 is required for ABA-induced ZmNAC84expression. Functional analysis reveals that ZmNAC84 is essential for ABA-induced antioxidant defense in a ZmCCaMK-dependent manner. Furthermore, ZmCCaMK directly phosphorylates Ser-113 of ZmNAC84 in vitro, and Ser-113 is essential for the ABA-induced stimulation of antioxidant defense by ZmCCaMK. Moreover, overexpression of ZmNAC84 in tobacco can improve drought tolerance and alleviate drought-induced oxidative damage of transgenic plants. These results define a mechanism for ZmCCaMK function in ABA-induced antioxidant defense, where ABA-produced H2O2 first induces expression of ZmCCaMK and ZmNAC84 and activates ZmCCaMK. Subsequently, the activated ZmCCaMK phosphorylates ZmNAC84 at Ser-113, thereby inducing antioxidant defense by activating downstream genes.

© 2016 The Author.Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1, an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rhamnogalacturonan II. Furthermore, these lines display reduced L-fucose content in N-glycan structures accompanied by severe developmental growth defects. We conclude that GFT1 is the major nucleotide sugar transporter for import of GDP-L-fucose into the Golgi and is required for proper plant growth and development.