scholarly journals Crucial Players for Inter-Organelle Communication: PI5P4Ks and Their Lipid Product PI-4,5-P2 Come to the Surface

Archna Ravi ◽  
Lavinia Palamiuc ◽  
Brooke M. Emerling

While organelles are individual compartments with specialized functions, it is becoming clear that organellar communication is essential for maintaining cellular homeostasis. This cooperation is carried out by various interactions taking place on the membranes of organelles. The membranes themselves contain a multitude of proteins and lipids that mediate these connections and one such class of molecules facilitating these relations are the phospholipids. There are several phospholipids, but the focus of this perspective is on a minor group called the phosphoinositides and specifically, phosphatidylinositol 4,5-bisphosphate (PI-4,5-P2). This phosphoinositide, on intracellular membranes, is largely generated by the non-canonical Type II PIPKs, namely, Phosphotidylinositol-5-phosphate-4-kinases (PI5P4Ks). These evolutionarily conserved enzymes are emerging as key stress response players in cells. Further, PI5P4Ks have been shown to modulate pathways by regulating organelle crosstalk, revealing roles in preserving metabolic homeostasis. Here we will attempt to summarize the functions of the PI5P4Ks and their product PI-4,5-P2 in facilitating inter-organelle communication and how they impact cellular health as well as their relevance to human diseases.

2021 ◽  
Vol 11 (1) ◽  
Yanxing Ma ◽  
Hainan Tian ◽  
Rao Lin ◽  
Wei Wang ◽  
Na Zhang ◽  

AbstractExpression of stress response genes can be regulated by abscisic acid (ABA) dependent and ABA independent pathways. Osmotic stresses promote ABA accumulation, therefore inducing the expression of stress response genes via ABA signaling. Whereas cold and heat stresses induce the expression of stress response genes via ABA independent pathway. ABA induced transcription repressors (AITRs) are a family of novel transcription factors that play a role in ABA signaling, and Drought response gene (DRG) has previously been shown to play a role in regulating plant response to drought and freezing stresses. We report here the identification of DRG as a novel transcription factor and a regulator of ABA response in Arabidopsis. We found that the expression of DRG was induced by ABA treatment. Homologs searching identified AITR5 as the most closely related Arabidopsis protein to DRG, and homologs of DRG, including the AITR-like (AITRL) proteins in bryophytes and gymnosperms, are specifically presented in embryophytes. Therefore we renamed DRG as AITRL. Protoplast transfection assays show that AITRL functioned as a transcription repressor. In seed germination and seedling greening assays, the aitrl mutants showed an increased sensitivity to ABA. By using qRT-PCR, we show that ABA responses of some ABA signaling component genes including some PYR1-likes (PYLs), PROTEIN PHOSPHATASE 2Cs (PP2Cs) and SUCROSE NONFERMENTING 1 (SNF1)-RELATED PROTEIN KINASES 2s (SnRK2s) were reduced in the aitrl mutants. Taken together, our results suggest that AITRLs are a family of novel transcription repressors evolutionally conserved in embryophytes, and AITRL regulates ABA response in Arabidopsis by affecting ABA response of some ABA signaling component genes.

Science ◽  
2021 ◽  
Vol 371 (6533) ◽  
pp. 1059-1063 ◽  
D. Dipon Ghosh ◽  
Dongyeop Lee ◽  
Xin Jin ◽  
H. Robert Horvitz ◽  
Michael N. Nitabach

Color detection is used by animals of diverse phyla to navigate colorful natural environments and is thought to require evolutionarily conserved opsin photoreceptor genes. We report that Caenorhabditis elegans roundworms can discriminate between colors despite the fact that they lack eyes and opsins. Specifically, we found that white light guides C. elegans foraging decisions away from a blue-pigment toxin secreted by harmful bacteria. These foraging decisions are guided by specific blue-to-amber ratios of light. The color specificity of color-dependent foraging varies notably among wild C. elegans strains, which indicates that color discrimination is ecologically important. We identified two evolutionarily conserved cellular stress response genes required for opsin-independent, color-dependent foraging by C. elegans, and we speculate that cellular stress response pathways can mediate spectral discrimination by photosensitive cells and organisms—even by those lacking opsins.

Dermatology ◽  
2019 ◽  
Vol 235 (5) ◽  
pp. 380-389 ◽  
Yeye Guo ◽  
Xu Zhang ◽  
Tianhao Wu ◽  
Xing Hu ◽  
Juan Su ◽  

Autophagy, or self-eating, is an evolutionarily conserved process in which cytosol and organelles are sequestered within double-membrane vesicles that deliver the contents to the lysosome/vacuole for the degradation and recycling of cytoplasmic components in eukaryotes. It is well recognized that autophagy plays an important role in maintaining cellular homeostasis under physiological and pathophysiological con­ditions and the upregulation of autophagy may serve as an adaptive process to provide nutrients and energy when under stresses. Recently, studies have illustrated that autophagy is intricately related to skin diseases. This review provides a brief synopsis of the process of autophagy and aims to elucidate the roles of autophagy in different skin diseases and to highlight the need for increased research in the field.

1996 ◽  
Vol 34 (3-4) ◽  
pp. 549-556 ◽  
P. J. Bliss ◽  
T. J. Schulz ◽  
T. Senger ◽  
R. B. Kaye

To identify factors affecting olfactometry panel performance in the measurement of environmental odours, a data bank of odour threshold measurements including 923 individual panel tests on environmental odours and 145 tests on standards were analysed statistically. There is an evident decrease in olfactory sensitivity to environmental odours with age. The group threshold tends to be one step lower for a 25 year increase in average age of panel members for Type I odours (piggery, feedlot, landfill and mushroom composting) and for 36 years increase for Type II odours (sewage and industrial coke works). The threshold for N-butanol tends to be 1 step lower for an increase of 15 years in age. People who are over 40 years old exhibited a greater variation than younger people. Although there was a minor gender difference in the sensitivity to butanol standard, it was not statistically significant (mean natural logarithm butanol threshold was 3.65 for males and 3.84 for females). Similar minor differences were exhibited in Confidence Index (CI), 1.72 for females (std. dev. 0.73) and 1.81 for males (std. dev. 0.77). Using “guess and correct” as criterion to determine individual thresholds in the forced choice olfactometry, the mean natural logarithm of ppb butanol is 1.365 lower than that for “certain and correct”. The standard deviation for “guess” and “certain” criteria were 1.093 and 0.911 respectively. The “certainty” criterion gave a better repeatability than the “guess” criterion.

Epigenomes ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 22 ◽  
Andrea Fuso

Textbook and scientific papers addressing DNA methylation usually still cite “DNA methylation occurs at CpG cytosines”. Methylation at cytosines outside the CpG nucleotide, the so-called “non-CpG methylation”, is usually considered a minor and not biologically relevant process. However, the technical improvements and additional studies in epigenetics have demonstrated that non-CpG methylation is present with frequency higher than previously thought and retains biological activity, potentially relevant to the understanding and the treatment of human diseases.

1992 ◽  
Vol 262 (6) ◽  
pp. R1106-R1110 ◽  
S. Okada ◽  
D. A. York ◽  
G. A. Bray

The effect of mifepristone (RU 486), a blocker of type II glucocorticoid receptors on the development of obesity that follows the feeding of a high-fat (HF) diet to Osborne-Mendel (OM) rats, has been investigated. OM rats fed a HF diet gained more weight and had larger retroperitoneal and parametrial fat pads than OM rats fed a high-carbohydrate low-fat (LF) diet. RU 486 (30 for 14 days completely reversed the body weight gain and the increase in fat pad size of OM rats fed a HF diet. RU 486 had no effect on body weight of OM rats fed a LF diet, but did reduce fat pad weights. The data suggest that type II glucocorticoid receptor activity modulates body fat deposition and is essential for the development of obesity, although a minor role for progestin receptor activity cannot be ruled out.

2018 ◽  
Vol 19 (12) ◽  
pp. 3940 ◽  
Po-Yuan Ke

Autophagy is an evolutionarily conserved cellular process in which intracellular components are eliminated via lysosomal degradation to supply nutrients for organelle biogenesis and metabolic homeostasis. Flavivirus infections underlie multiple human diseases and thus exert an immense burden on public health worldwide. Mounting evidence indicates that host autophagy is subverted to modulate the life cycles of flaviviruses, such as hepatitis C virus, dengue virus, Japanese encephalitis virus, West Nile virus and Zika virus. The diverse interplay between autophagy and flavivirus infection not only regulates viral growth in host cells but also counteracts host stress responses induced by viral infection. In this review, we summarize the current knowledge on the role of autophagy in the flavivirus life cycle. We also discuss the impacts of virus-induced autophagy on the pathogeneses of flavivirus-associated diseases and the potential use of autophagy as a therapeutic target for curing flavivirus infections and related human diseases.

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