scholarly journals The 4E-BP growth pathway regulates the effect of ambient temperature onDrosophilametabolism and lifespan

2017 ◽  
Vol 114 (36) ◽  
pp. 9737-9742 ◽  
Author(s):  
Gil B. Carvalho ◽  
Ilaria Drago ◽  
Sany Hoxha ◽  
Ryuichi Yamada ◽  
Olena Mahneva ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Mitochondrial Protein ◽  
Model Organism ◽  
Protein Translation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Metabolic Switch ◽  
Eukaryotic Translation ◽  
Eukaryotic Translation Initiation ◽  
Underlying Mechanisms

Changes in body temperature can profoundly affect survival. The dramatic longevity-enhancing effect of cold has long been known in organisms ranging from invertebrates to mammals, yet the underlying mechanisms have only recently begun to be uncovered. In the nematodeCaenorhabditis elegans, this process is regulated by a thermosensitive membrane TRP channel and the DAF-16/FOXO transcription factor, but in more complex organisms the underpinnings of cold-induced longevity remain largely mysterious. We report that, inDrosophila melanogaster, variation in ambient temperature triggers metabolic changes in protein translation, mitochondrial protein synthesis, and posttranslational regulation of the translation repressor, 4E-BP (eukaryotic translation initiation factor 4E-binding protein). We show that 4E-BP determinesDrosophilalifespan in the context of temperature changes, revealing a genetic mechanism for cold-induced longevity in this model organism. Our results suggest that the 4E-BP pathway, chiefly thought of as a nutrient sensor, may represent a master metabolic switch responding to diverse environmental factors.

scholarly journals APOL1 risk variants cause podocytes injury through enhancing endoplasmic reticulum stress

2018 ◽  
Vol 38 (4) ◽  
Author(s):  
Hongxiu Wen ◽  
Vinod Kumar ◽  
Xiqian Lan ◽  
Seyedeh Shadafarin Marashi Shoshtari ◽  
Judith M. Eng ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Kidney Diseases ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Wild Type ◽  
Eukaryotic Translation ◽  
Risk Variants ◽  
Eukaryotic Translation Initiation ◽  
Underlying Mechanisms

Two coding sequence variants (G1 and G2) of Apolipoprotein L1 (APOL1) gene have been implicated as a higher risk factor for chronic kidney diseases (CKD) in African Americans when compared with European Americans. Previous studies have suggested that the APOL1 G1 and G2 variant proteins are more toxic to kidney cells than the wild-type APOL1 G0, but the underlying mechanisms are poorly understood. To determine whether endoplasmic reticulum (ER) stress contributes to podocyte toxicity, we generated human podocytes (HPs) that stably overexpressed APOL1 G0, G1, or G2 (Vec/HPs, G0/HPs, G1/HPs, and G2/HPs). Propidium iodide staining showed that HP overexpressing the APOL1 G1 or G2 variant exhibited a higher rate of necrosis when compared with those overexpressing the wild-type G0 counterpart. Consistently, the expression levels of nephrin and podocin proteins were significantly decreased in the G1- or G2-overexpressing cells despite the maintenance of their mRNA expressions levels. In contrast, the expression of the 78-kDa glucose-regulated protein ((GRP78), also known as the binding Ig protein, BiP) and the phosphorylation of the eukaryotic translation initiation factor 1 (eIF1) were significantly elevated in the G1/HPs and G2/HPs, suggesting a possible occurrence of ER stress in these cells. Furthermore, ER stress inhibitors not only restored nephrin protein expression, but also provided protection against necrosis in G1/HPs and G2/HPs, suggesting that APOL1 risk variants cause podocyte injury partly through enhancing ER stress.

scholarly journals Regulation of eIF2α Phosphorylation by MAPKs Influences Polysome Stability and Protein Translation

2021 ◽  
Author(s):  
Sana Parveen ◽  
Haripriya Parthasarathy ◽  
Dhiviya Vedagiri ◽  
Divya Gupta ◽  
Hitha Gopalan Nair ◽  
...  
Keyword(s):  
P38 Mapk ◽  
Protein Translation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Translation Regulation ◽  
Eukaryotic Translation ◽  
Eif2α Phosphorylation ◽  
Mitogen Activated Protein ◽  
Eukaryotic Translation Initiation ◽  
Polysome Stability

Regulation of protein translation occurs primarily at the level of initiation and is mediated by multiple signaling pathways, majorly mechanistic target of rapamycin complex 1 (mTORC1), mitogen-activated protein kinases (MAPKs), and the eukaryotic translation initiation factor eIF2. While mTORC1 and eIF2α influence the polysome stability, MAPKs influence the phosphorylation of the cap-binding protein eIF4E and are known to influence translation of only a small set of mRNAs. Here, we demonstrate that p38 MAPK and ERK1/2 regulate translation through integrated stress response (ISR) pathways. Dual inhibition (dual-Mi) of p38 MAPK and ERK1/2 caused substantial phosphorylation of eIF2α in a synergistic manner, resulting in near-absolute collapse of polysomes. This regulation was independent of Mnk1/2, a well-studied mediator of translation regulation by the MAPKs. Dual-Mi-induced polysome dissociation was far more striking than that caused by sodium arsenite, a strong inducer of ISR. Interestingly, induction of ISR caused increased p38 phosphorylation, and its inhibition resulted in stronger polysome dissociation, indicating the importance of p38 in the translation activities. Thus, our studies demonstrate a major, unidentified role for ERK1/2 and more particularly p38 MAPK in the maintenance of homeostasis of polysome association and translation activities.

The role of Eif2s3y in mouse spermatogenesis

2021 ◽  
Vol 16 ◽  
Author(s):  
Wenqing Liu ◽  
Na Li ◽  
Mengfei Zhang ◽  
Ahmed H. Arisha ◽  
Jinlian Hua
Keyword(s):  
Translation Initiation ◽  
Mrna Translation ◽  
Protein Translation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Gene Encoding ◽  
Eukaryotic Translation ◽  
Initiation Factor 2 ◽  
Eukaryotic Translation Initiation

: Eukaryotic translation initiation factor 2 subunit 3 and structural gene Y-linked (Eif2s3y) gene, the gene encoding eIF2γ protein, is located on the mouse Y chromosome short arm. The Eif2s3y gene is globally expressed in all tissues and plays an important role in regulating global and gene-specific mRNA translation initiation. During the process of protein translation initiation, Eif2s3x(its homolog) and Eif2s3y encoded eIF2γ perform similar functions. However, it has been noticed that Eif2s3y plays a crucial role in spermatogenesis, including spermatogonia mitosis, meiosis, and spermiogenesis of spermatids, which may account for infertility. In the period of spermatogenesis, the role of Eif2s3x and Eif2s3y are not equivalent. Importance of Eif2s3y has been observed in ESC and implicated in several aspects, including the pluripotency state and the proliferation rate. Here, we discuss the functional significance of Eif2s3y in mouse spermatogenesis and self-renewal of ESCs.

scholarly journals Distinct Roles of mTOR Targets S6K1 and S6K2 in Breast Cancer

2020 ◽  
Vol 21 (4) ◽  
pp. 1199 ◽  
Author(s):  
Savitha Sridharan ◽  
Alakananda Basu
Keyword(s):  
Breast Cancer ◽  
Protein Translation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Eukaryotic Translation ◽  
Eukaryotic Translation Initiation ◽  
And Function ◽  
Cell Growth And Proliferation ◽  
High Degree ◽  
Mtor Complex 1

The mechanistic target of rapamycin (mTOR) is a master regulator of protein translation, metabolism, cell growth and proliferation. It forms two complexes, mTOR complex 1 (mTORC1) and 2 (mTORC2). mTORC1 is frequently deregulated in many cancers, including breast cancer, and is an important target for cancer therapy. The immunosuppressant drug rapamycin and its analogs that inhibit mTOR are currently being evaluated for their potential as anti-cancer agents, albeit with limited efficacy. mTORC1 mediates its function via its downstream targets 40S ribosomal S6 kinases (S6K) and eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1). There are two homologs of S6K: S6K1 and S6K2. Most of the earlier studies focused on S6K1 rather than S6K2. Because of their high degree of structural homology, it was generally believed that they behave similarly. Recent studies suggest that while they may share some functions, they may also exhibit distinct or even opposite functions. Both homologs have been implicated in breast cancer, although how they contribute to breast cancer may differ. The purpose of this review article is to compare and contrast the expression, structure, regulation and function of these two S6K homologs in breast cancer.

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