1.Jasmonates: signal transduction components and their roles in environmental stress responses.
Goossens J1,2, Fernández-Calvo P1,2, Schweizer F1,2, Goossens A3,4. Plant Mol Biol. 2016 Apr 16. [Epub ahead of print]
Jasmonates, oxylipin-type plant hormones, are implicated in diverse aspects of plant growth development and interaction with the environment. Following diverse developmental and environmental cues, jasmonate is produced, conjugated to the amino acid isoleucine and perceived by a co-receptor complex composed of the Jasmonate ZIM-domain (JAZ) repressor proteins and an E3 ubiquitin ligase complex containing the F-box CORONATINE INSENSITIVE 1 (COI1). This event triggers the degradation of the JAZ proteins and the release of numerous transcription factors, including MYC2 and its homologues, which are otherwise bound and inhibited by the JAZ repressors. Here, we will review the role of the COI1, JAZ and MYC2 proteins in the interaction of the plant with its environment, illustrating the significance of jasmonate signalling, and of the proteins involved, for responses to both biotic stresses caused by insects and numerous microbial pathogens and abiotic stresses caused by adverse climatic conditions.
2.Plasma amino acid and metabolite signatures tracking diabetes progression in the UCD-T2DM Rat model of type 2 diabetes.
Piccolo BD1, Graham JL2, Stanhope KL2, Fiehn O2, Havel PJ2, Adams SH3. Am J Physiol Endocrinol Metab. 2016 Apr 19:ajpendo.00052.2016. doi: 10.1152/ajpendo.00052.2016. [Epub ahead of print]
Elevations of plasma concentrations of branched-chain amino acids (BCAAs) are observed in human insulin resistance and type 2 diabetes mellitus (T2DM); however, there has been some controversy with respect to the passive or causative nature of the BCAA phenotype. Using untargeted metabolomics, plasma BCAA and other metabolites were assessed in lean control Sprague-Dawley rats (LC) and temporally during diabetes development in the UCD-T2DM Rat model: i.e., pre-diabetic (PD), 2-weeks (D2W), 3-months (D3M) and 6-months (D6M) post-onset of diabetes. Plasma leucine, isoleucine, and valine concentrations were elevated only in D6M rats compared with D2W rats (by 28%, 29%, and 30%, respectively). This was in contrast to decreased plasma concentrations of several other amino acids in D3M and/or D6M relative to LC rats (Ala, Arg, Glu, Gln, Met, Ser, Thr, Trp). BCAAs were positively correlated with fasting glucose and negatively correlated with plasma insulin, total body weight, total adipose tissue weight, and gastrocnemius muscle weight in D3M and D6M groups.
3.A conserved patch of hydrophobic amino acids modulates Myb activity by mediating protein-protein interactions.
Dukare S1, Klempnauer KH2. Biochim Biophys Acta. 2016 Apr 11. pii: S1874-9399(16)30064-5. doi: 10.1016/j.bbagrm.2016.04.004. [Epub ahead of print]
The transcription factor c-Myb plays a key role in the control of proliferation and differentiation in hematopoietic progenitor cells and has been implicated in the development of leukemia and certain non-hematopoietic tumors. c-Myb activity is highly dependent on the interaction with the coactivator p300 which is mediated by the transactivation domain of c-Myb and the KIX domain of p300. We have previously observed that conservative valine-to-isoleucine amino acid substitutions in a conserved stretch of hydrophobic amino acids have a profound effect on Myb activity. Here, we have explored the function of the hydrophobic region as a mediator of protein-protein interactions. We show that the hydrophobic region facilitates Myb self-interaction and binding of the histone acetyl transferase Tip60, a previously identified Myb interacting protein. We show that these interactions are affected by the valine-to-isoleucine amino acid substitutions and suppress Myb activity by interfering with the interaction of Myb and the KIX domain of p300.
4.Single nucleotide polymorphisms in glutathione S-transferase P1 and M1 genes and overall survival of patients with ovarian serous cystadenocarcinoma treated with chemotherapy.
Cong LX1, Zhai XH2, Wu FX3, Zhu DY1, Wang AC1. Oncol Lett. 2016 Apr;11(4):2525-2531. Epub 2016 Feb 11.
The effects of platinum-based drugs are controlled by genes that are involved in DNA detoxification, including glutathione S-transferase (GST)P1 and GSTM1, which have been associated with increased benefits in the chemotherapeutic treatment of patients with ovarian cancer. The present study assessed the effect of single nucleotide polymorphisms in GST genes on the overall survival (OS) of patients with ovarian serous cystadenocarcinoma that were treated with chemotherapy. A total of 95 patients received treatment with a carboplatin-based or alternative chemotherapy. Polymorphisms in the patients were genotyped using the following methods: Pyrosequencing, to identify GSTP1 Ile105Val; a relative quantification method, to identify the copy number variation in GSTM1; and polymerase chain reaction followed by gel electrophoresis, to identify the null vs. non-null genotypes of GSTM1. The association between genotypes and OS of patients was assessed using Kaplan-Meier survival curves and Cox proportional hazards regression analysis.