Mingxiao Feng, and Jae-Yean KimMol. Cells 2015; 38(10): 829-835 https://doi.org/10.14348/molcells.2015.0205
Abstract : It has been suggested that AUXIN BINDING PROTEIN 1 (ABP1) functions as an apoplastic auxin receptor, and is known to be involved in the post-transcriptional process, and largely independent of the already well-known SKP-cullin-F-box-transport inhibitor response (TIR1) /auxin signaling F-box (AFB) (SCFTIR1/AFB) pathway. In the past 10 years, several key components downstream of ABP1 have been reported. After perceiving the auxin signal, ABP1 interacts, directly or indirectly, with plasma membrane (PM)-localized transmembrane proteins, transmembrane kinase (TMK) or SPIKE1 (SPK1), or other unidentified proteins, which transfer the signal into the cell to the Rho of plants (ROP). ROPs interact with their effectors, such as the ROP interactive CRIB motif-containing protein (RIC), to regulate the endocytosis/exocytosis of the auxin efflux carrier PIN-FORMED (PIN) proteins to mediate polar auxin transport across the PM. Additionally, ABP1 is a negative regulator of the traditional SCFTIR1/AFB auxin signaling pathway. However,
Dandan Zhang, Qiang Zhao, and Beili WuMol. Cells 2015; 38(10): 836-842 https://doi.org/10.14348/molcells.2015.0263
Abstract : G protein-coupled receptors (GPCRs) constitute the largest and the most physiologically important membrane protein family that recognizes a variety of environmental stimuli, and are drug targets in the treatment of numerous diseases. Recent progress on GPCR structural studies shed light on molecular mechanisms of GPCR ligand recognition, activation and allosteric modulation, as well as structural basis of GPCR dimerization. In this review, we will discuss the structural features of GPCRs and structural insights of different aspects of GPCR biological functions.
Jung Hwan Hwang, Yong-Hoon Kim, Jung-Ran Noh, Dong-Hee Choi, Kyoung-Shim Kim, and Chul-Ho LeeMol. Cells 2015; 38(10): 843-850 https://doi.org/10.14348/molcells.2015.0072
Abstract : The hepatic cell death induced by acetaminophen (APAP) is closely related to cellular adenosine triphosphate (ATP) depletion, which is mainly caused by mitochondrial dysfunction. Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a key sensor of low energy status. AMPK regulates metabolic homeostasis by stimulating catabolic metabolism and suppressing anabolic pathways to increase cellular energy levels. We found that the decrease in active phosphorylation of AMPK in response to APAP correlates with decreased ATP levels,
Jihwa Chung, Kyoung Hwa Kim, Seok Cheol Lee, Shung Hyun An, and Kihwan KwonMol. Cells 2015; 38(10): 851-858 https://doi.org/10.14348/molcells.2015.0094
Abstract : Disturbed blood flow with low-oscillatory shear stress (OSS) is a predominant atherogenic factor leading to dysfunctional endothelial cells (ECs). Recently, it was found that disturbed flow can directly induce endoplasmic reticulum (ER) stress in ECs, thereby playing a critical role in the development and progression of atherosclerosis. Ursodeoxycholic acid (UDCA), a naturally occurring bile acid, has long been used to treat chronic cholestatic liver disease and is known to alleviate endoplasmic reticulum (ER) stress at the cellular level. However, its role in atherosclerosis remains unexplored. In this study, we demonstrated the anti-atherogenic activity of UDCA via inhibition of disturbed flow-induced ER stress in atherosclerosis. UDCA effectively reduced ER stress, resulting in a reduction in expression of X-box binding protein-1 (XBP-1) and CEBP-homologous protein (CHOP) in ECs. UDCA also inhibits the disturbed flow-induced inflammatory responses such as increases in adhesion molecules, monocyte adhesion to ECs, and apoptosis of ECs. In a mouse model of disturbed flow-induced atherosclerosis, UDCA inhibits atheromatous plaque formation through the alleviation of ER stress and a decrease in adhesion molecules. Taken together, our results revealed that UDCA exerts anti-atherogenic activity in disturbed flow-induced atherosclerosis by inhibiting ER stress and the inflammatory response. This study suggests that UDCA may be a therapeutic agent for prevention or treatment of atherosclerosis.
Jing Guo, Hongjuan He, Qi Liu, Fengwei Zhang, Jie Lv, Tiebo Zeng, Ning Gu, and Qiong WuMol. Cells 2015; 38(10): 859-865 https://doi.org/10.14348/molcells.2015.0098
Abstract : Most imprinted genes are concerned with embryonic development, especially placental development. Here, we identified a placenta-specific imprinted gene
Hee-Kyung Ahn, Yong Won Kang, Hye Min Lim, Inhwan Hwang, and Hyun-Sook PaiMol. Cells 2015; 38(10): 866-875 https://doi.org/10.14348/molcells.2015.0115
Abstract : COPI vesicles are essential to the retrograde transport of proteins in the early secretory pathway. The COPI coatomer complex consists of seven subunits, termed α-, β-, β′-, γ-, δ-, ε-, and ζ-COP, in yeast and mammals. Plant genomes have homologs of these subunits, but the essentiality of their cellular functions has hampered the functional characterization of the subunit genes in plants. Here we have employed virus-induced gene silencing (VIGS) and dexamethasone (DEX)-inducible RNAi of the COPI subunit genes to study the
Md. Ariful Islam, Syeda Ridita Sharif, HyunSook Lee, and Il Soo MoonMol. Cells 2015; 38(10): 876-885 https://doi.org/10.14348/molcells.2015.0120
Qihui Liu, Yuan Tian, Xiangfeng Zhao, Haifeng Jing, Qi Xie, Peng Li, Dong Li, Dongmei Yan, and Xun ZhuMol. Cells 2015; 38(10): 886-894 https://doi.org/10.14348/molcells.2015.0125
Abstract : Macrophages are divided into two subpopulations: classically activated macrophages (M1) and alternatively activated macrophages (M2). BCG (Bacilli Calmette-Gu?rin) activates disabled na?ve macrophages to M1 macrophages, which act as inflammatory, microbicidal and tumoricidal cells through cell-cell contact and/or the release of soluble factors. Various transcription factors and signaling pathways are involved in the regulation of macrophage activation and polarization. We discovered that BCG-activated macrophages (BAM) expressed a new molecule, and we named it Novel Macrophage Activated Associated Protein 1 (NMAAP1).The current study found that the overexpression of NMAAP1 in macrophages results in M1 polarization with increased expression levels of M1 genes, such as inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), Interleukin 6 (IL-6), Interleukin 12 (IL-12), Monocyte chemoattractant protein-1 (MCP-1) and Interleukin-1 beta (IL-1β), and decreased expression of some M2 genes, such as Kruppel-like factor 4 (KLF4) and suppressor of cytokine signaling 1 (SOCS1), but not other M2 genes, including arginase-1 (Arg-1), Interleukin (IL-10), transforming growth factor beta (TGF-β) and found in inflammatory zone 1 (Fizz1). Moreover, NMAAP1 overexpression in the RAW264.7 cell line increased cytotoxicity against MCA207 tumor cells, which depends on increased inflammatory cytokines rather than cell-cell contact. NMAAP1 also substantially enhanced the phagocytic ability of macrophages, which implies that NMAAP1 promoted macrophage adhesive and clearance activities. Our results indicate that NMAAP1 is an essential molecule that modulates macrophages phenotype and plays an important role in macrophage tumoricidal functions.
Jinhyuk Bhin, Hoe-Su Jeong, Jong Soo Kim, Jeong Oh Shin, Ki Sung Hong, Han-Sung Jung, Changhoon Kim, Daehee Hwang, and Kye-Seong KimMol. Cells 2015; 38(10): 895-903 https://doi.org/10.14348/molcells.2015.0146
Abstract : Non-coding microRNAs (miRNAs) regulate the translation of target messenger RNAs (mRNAs) involved in the growth and development of a variety of cells, including primordial germ cells (PGCs) which play an essential role in germ cell development. However, the target mRNAs and the regulatory networks influenced by miRNAs in PGCs remain unclear. Here, we demonstrate a novel miRNAs control PGC development through targeting mRNAs involved in various cellular pathways. We reveal the PGC-enriched expression patterns of nine miRNAs, including miR-10b, -18a, -93, -106b, -126-3p, -127, -181a, -181b, and -301, using miRNA expression analysis along with mRNA microarray analysis in PGCs, embryonic gonads, and postnatal testes. These miRNAs are highly expressed in PGCs, as demonstrated by Northern blotting, miRNA in situ hybridization assay, and miRNA qPCR analysis. This integrative study utilizing mRNA microarray analysis and miRNA target prediction demonstrates the regulatory networks through which these miRNAs regulate their potential target genes during PGC development. The elucidated networks of miRNAs disclose a coordinated molecular mechanism by which these miRNAs regulate distinct cellular pathways in PGCs that determine germ cell development.
Jung Ha Kim, Kabsun Kim, Inyoung Kim, Semun Seong, and Nacksung KimMol. Cells 2015; 38(10): 904-910 https://doi.org/10.14348/molcells.2015.0177
Abstract : Negative regulator of reactive oxygen species (NRROS) is known to repress ROS generation in phagocytes. In this study, we examined the roles of NRROS in both osteoclasts and osteoblasts. Our results demonstrate that NRROS negatively regulates the differentiation of osteoclasts, but not osteoblasts. Further, overexpression of NRROS in osteoclast precursor cells attenuates RANKL-induced osteoclast differentiation. Conversely, osteoclast differentiation is enhanced upon siRNA-mediated knockdown of NRROS. Additionally, NRROS attenuates RANKL-induced NF-κB activation, as well as degradation of the NOX1 and NOX2 proteins, which are required for ROS generation. Based on our observations, we present NRROS as a novel negative regulator of RANKL-induced osteoclastogenesis.