Faculty Opinions recommendation of Plasma Membrane CRPK1-Mediated Phosphorylation of 14-3-3 Proteins Induces Their Nuclear Import to Fine-Tune CBF Signaling during Cold Response.

Drosophila melanogaster Armadillo plays two distinct roles during development. It is a component of adherens junctions, and functions as a transcriptional activator in response to Wingless signaling. In the current model, Wingless signal causes stabilization of cytoplasmic Armadillo allowing it to enter the nucleus where it can activate transcription. However, the mechanism of nuclear import and export remains to be elucidated. In this study, we show that two gain-of-function alleles of Armadillo activate Wingless signaling by different mechanisms. The S10 allele was previously found to localize to the nucleus, where it activates transcription. In contrast, the ΔArm allele localizes to the plasma membrane, and forces endogenous Arm into the nucleus. Therefore, ΔArm is dependent on the presence of a functional endogenous allele of arm to activate transcription. We show that ΔArm may function by titrating Axin protein to the membrane, suggesting that it acts as a cytoplasmic anchor keeping Arm out of the nucleus. In axin mutants, Arm is localized to the nuclei. We find that nuclear retention is dependent on dTCF/Pangolin. This suggests that cellular distribution of Arm is controlled by an anchoring system, where various nuclear and cytoplasmic binding partners determine its localization.

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Pentagone internalises glypicans to fine-tune multiple signalling pathways

eLife ◽

10.7554/elife.13301 ◽

2016 ◽

Vol 5 ◽

Cited By ~ 19

Author(s):

Mark Norman ◽

Robin Vuilleumier ◽

Alexander Springhorn ◽

Jennifer Gawlik ◽

George Pyrowolakis

Keyword(s):

Plasma Membrane ◽

Fine Tuning ◽

Signalling Pathways ◽

Wing Development ◽

Secreted Protein ◽

Drosophila Wing ◽

Reception System ◽

Bmp Signalling ◽

Fine Tune

Tight regulation of signalling activity is crucial for proper tissue patterning and growth. Here we investigate the function of Pentagone (Pent), a secreted protein that acts in a regulatory feedback during establishment and maintenance of BMP/Dpp morphogen signalling during Drosophila wing development. We show that Pent internalises the Dpp co-receptors, the glypicans Dally and Dally-like protein (Dlp), and propose that this internalisation is important in the establishment of a long range Dpp gradient. Pent-induced endocytosis and degradation of glypicans requires dynamin- and Rab5, but not clathrin or active BMP signalling. Thus, Pent modifies the ability of cells to trap and transduce BMP by fine-tuning the levels of the BMP reception system at the plasma membrane. In addition, and in accordance with the role of glypicans in multiple signalling pathways, we establish a requirement of Pent for Wg signalling. Our data propose a novel mechanism by which morphogen signalling is regulated.

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The Subcellular Localization of an Aquaporin-2 Tetramer Depends on the Stoichiometry of Phosphorylated and Nonphosphorylated Monomers

The Journal of Cell Biology ◽

10.1083/jcb.151.4.919 ◽

2000 ◽

Vol 151 (4) ◽

pp. 919-930 ◽

Cited By ~ 126

Author(s):

E.J. Kamsteeg ◽

I. Heijnen ◽

C.H. van Os ◽

P.M.T. Deen

Keyword(s):

Plasma Membrane ◽

Steady State ◽

Subcellular Localization ◽

Water Channel ◽

Apical Plasma Membrane ◽

Wild Type ◽

Principal Cells ◽

Intracellular Vesicles ◽

And Function ◽

Fine Tune

In renal principal cells, vasopressin regulates the shuttling of the aquaporin (AQP)2 water channel between intracellular vesicles and the apical plasma membrane. Vasopressin-induced phosphorylation of AQP2 at serine 256 (S256) by protein kinase A (PKA) is essential for its localization in the membrane. However, phosphorylated AQP2 (p-AQP2) has also been detected in intracellular vesicles of noninduced principal cells. As AQP2 is expressed as homotetramers, we hypothesized that the number of p-AQP2 monomers in a tetramer might be critical for the its steady state distribution. Expressed in oocytes, AQP2-S256D and AQP2-S256A mimicked p-AQP2 and non–p-AQP2, respectively, as routing and function of AQP2-S256D and wild-type AQP2 (wt-AQP2) were identical, whereas AQP2-S256A was retained intracellularly. In coinjection experiments, AQP2-S256A and AQP2-S256D formed heterotetramers. Coinjection of different ratios of AQP2-S256A and AQP2-S256D cRNAs revealed that minimally three AQP2-S256D monomers in an AQP2 tetramer were essential for its plasma membrane localization. Therefore, our results suggest that in principal cells, minimally three monomers per AQP2 tetramer have to be phosphorylated for its steady state localization in the apical membrane. As other multisubunit channels are also regulated by phosphorylation, it is anticipated that the stoichiometry of their phosphorylated and nonphosphorylated subunits may fine-tune the activity or subcellular localization of these complexes.

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INPP5K and Atlastin-1 maintain the nonuniform distribution of ER–plasma membrane contacts in neurons

Life Science Alliance ◽

10.26508/lsa.202101092 ◽

2021 ◽

Vol 4 (11) ◽

pp. e202101092

Author(s):

Jingbo Sun ◽

Raihanah Harion ◽

Tomoki Naito ◽

Yasunori Saheki

Keyword(s):

Plasma Membrane ◽

Neurological Disorders ◽

Nonuniform Distribution ◽

Forward Genetic Screen ◽

Cellular Processes ◽

Multiple Contacts ◽

Membrane Contacts ◽

Unique Distribution ◽

Neuronal Physiology ◽

Fine Tune

In neurons, the ER extends throughout all cellular processes, forming multiple contacts with the plasma membrane (PM) to fine-tune neuronal physiology. However, the mechanisms that regulate the distribution of neuronal ER-PM contacts are not known. Here, we used the Caenorhabditis elegans DA9 motor neuron as our model system and found that neuronal ER-PM contacts are enriched in soma and dendrite and mostly absent in axons. Using forward genetic screen, we identified that the inositol 5-phosphatase, CIL-1 (human INPP5K), and the dynamin-like GTPase, ATLN-1 (human Atlastin-1), help to maintain the non-uniform, somatodendritic enrichment of neuronal ER-PM contacts. Mechanistically, CIL-1 acts upstream of ATLN-1 to maintain the balance between ER tubules and sheets. In mutants of CIL-1 or ATLN-1, ER sheets expand and invade into the axon. This is accompanied by the ectopic formation of axonal ER-PM contacts and defects in axon regeneration following laser-induced axotomy. As INPP5K and Atlastin-1 have been linked to neurological disorders, the unique distribution of neuronal ER-PM contacts maintained by these proteins may support neuronal resilience during the onset and progression of these diseases.

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Expanding TOR Complex 2 Signaling: Emerging Regulators and New Connections

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.713806 ◽

2021 ◽

Vol 9 ◽

Author(s):

Peng An ◽

Wenyi Xu ◽

Junjie Luo ◽

Yongting Luo

Keyword(s):

Plasma Membrane ◽

Membrane Proteins ◽

Cell Survival ◽

Signaling Pathways ◽

Environmental Cues ◽

Comprehensive Overview ◽

Cellular Homeostasis ◽

Tor Pathway ◽

Fine Tune ◽

Upstream Regulators

Almost three decades after its seminal discovery, our understanding of the remarkable TOR pathway continues to expand. As a TOR complex, TORC2 lies at the nexus of many signaling pathways and directs a diverse array of fundamental processes such as cell survival, proliferation, and metabolism by integrating environmental and intracellular cues. The dysregulation of TORC2 activity disrupts cellular homeostasis and leads to many pathophysiological conditions. With continued efforts at mapping the signaling landscape, the pace of discovery in TORC2 regulation has been accelerated in recent years. Consequently, emerging evidence has expanded the repertoire of upstream regulators and has revealed unexpected diversity in the modes of TORC2 regulation. Multiple environmental cues and plasma membrane proteins that fine-tune TORC2 activity are unfolding. Furthermore, TORC2 signaling is intricately intertwined with other major signaling pathways. Therefore, feedback and crosstalk regulation also extensively modulate TORC2. In this context, we provide a comprehensive overview of revolutionary concepts regarding emerging regulators of TORC2 and discuss evidence of feedback and crosstalk regulation that shed new light on TORC2 biology.

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Cold Temperature Induces the Reprogramming of Proteolytic Pathways in Yeast

Journal of Biological Chemistry ◽

10.1074/jbc.m115.698662 ◽

2015 ◽

Vol 291 (4) ◽

pp. 1664-1675 ◽

Cited By ~ 11

Author(s):

Marta Isasa ◽

Clara Suñer ◽

Miguel Díaz ◽

Pilar Puig-Sàrries ◽

Alice Zuin ◽

...

Keyword(s):

Plasma Membrane ◽

Membrane Proteins ◽

Low Temperature ◽

Reference Strain ◽

Cellular Reprogramming ◽

Signaling System ◽

Plasma Membrane Proteins ◽

Cold Response ◽

Proteolytic Pathways

Despite much evidence of the involvement of the proteasome-ubiquitin signaling system in temperature stress response, the dynamics of the ubiquitylome during cold response has not yet been studied. Here, we have compared quantitative ubiquitylomes from a strain deficient in proteasome substrate recruitment and a reference strain during cold response. We have observed that a large group of proteins showing increased ubiquitylation in the proteasome mutant at low temperature is comprised by reverses suppressor of Ty-phenotype 5 (Rsp5)-regulated plasma membrane proteins. Analysis of internalization and degradation of plasma membrane proteins at low temperature showed that the proteasome becomes determinant for this process, whereas, at 30 °C, the proteasome is dispensable. Moreover, our observations indicate that proteasomes have increased capacity to interact with lysine 63-polyubiquitylated proteins during low temperature in vivo. These unanticipated observations indicate that, during cold response, there is a proteolytic cellular reprogramming in which the proteasome acquires a role in the endocytic-vacuolar pathway.

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Herbal Prescription, DSGOST, Prevents Cold-Induced RhoA Activation and Endothelin-1 Production in Endothelial Cells

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2014/549307 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 8

Author(s):

Sung-Gook Cho ◽

Ho Yeon Go ◽

Jeong-Su Park ◽

Ki-Yong Jung ◽

Seung-Ho Sun ◽

...

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Plasma Membrane ◽

Cell Types ◽

Biological Mechanism ◽

Cold Response ◽

Endothelin 1 ◽

Rhoa Activity ◽

Rhoa Activation ◽

Herbal Prescription

Herbal prescription, Danggui-Sayuk-Ga-Osuyu-Saenggang-tang (DSGOST), has long been used to treat Raynaud’s phenomenon (RP) in traditional Chinese medicine (TCM). However, a biological mechanism by which DSGOST ameliorates RP is yet deciphered. In this study, we demonstrate that DSGOST inhibits cold-induced activation of RhoA, in both vascular smooth muscle cells (VSMC) and endothelial cells (EC), and blocks endothelin-1-mediated paracrine path for cold response on vessels. While cold induced RhoA activity in both cell types, DSGOST pretreatment prevented cold-induced RhoA activation. DSGOST inhibition of cold-induced RhoA activation further blockedα2c-adrenoreceptor translocation to the plasma membrane in VSMC. In addition, DSGOST inhibited endothelin-1-mediated RhoA activation andα2c-adrenoreceptor translocation in VSMC. Meanwhile, DSGOST inhibited cold-induced or RhoA-dependent phosphorylation of FAK, SRC, and ERK. Consistently, DSGOST inhibited cold-induced endothelin-1 expression in EC. Therefore, DSGOST prevents cold-induced RhoA in EC and blocks endothelin-1-mediated paracrine path between EC and VSMC. In conclusion, our data suggest that DSGOST is beneficial for treating RP-like syndrome.

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Dimerization of MLH1 and PMS2 Limits Nuclear Localization of MutLα

Molecular and Cellular Biology ◽

10.1128/mcb.23.9.3320-3328.2003 ◽

2003 ◽

Vol 23 (9) ◽

pp. 3320-3328 ◽

Cited By ~ 54

Author(s):

Xiaosheng Wu ◽

Jeffrey L. Platt ◽

Marilia Cascalho

Keyword(s):

Mismatch Repair ◽

Nuclear Localization ◽

Dna Sequences ◽

Nuclear Import ◽

Nuclear Export ◽

Genomic Stability ◽

Dna Damage And Repair ◽

Nuclear Localization Signals ◽

Dna Mismatch ◽

Fine Tune

ABSTRACT DNA mismatch repair maintains genomic stability by detecting and correcting mispaired DNA sequences and by signaling cell death when DNA repair fails. The mechanism by which mismatch repair coordinates DNA damage and repair with cell survival or death is not understood, but it suggests the need for regulation. Since the functions of mismatch repair are initiated in the nucleus, we asked whether nuclear transport of MLH1 and PMS2 is limiting for the nuclear localization of MutLα (the MLH1-PMS2 dimer). We found that MLH1 and PMS2 have functional nuclear localization signals (NLS) and nuclear export sequences, yet nuclear import depended on their C-terminal dimerization to form MutLα. Our studies are consistent with the idea that dimerization of MLH1 and PMS2 regulates nuclear import by unmasking the NLS. Limited nuclear localization of MutLα may thus represent a novel mechanism by which cells fine-tune mismatch repair functions. This mechanism may have implications in the pathogenesis of hereditary non-polyposis colon cancer.

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513 Use of Reverse Transcription PCR (RT-PCR) to Study the Potato Stearoyl-ACP Desaturase (Delta9) Gene Expression at the Transcript Level during Cold Acclimation

HortScience ◽

10.21273/hortsci.34.3.534b ◽

1999 ◽

Vol 34 (3) ◽

pp. 534B-534

Author(s):

Sandra E. Vega ◽

Jiwan P. Palta

Keyword(s):

Plasma Membrane ◽

Cold Acclimation ◽

Transcript Level ◽

Desaturase Gene ◽

Cold Response ◽

Reverse Transcription Pcr ◽

Before And After ◽

Cold Tolerant ◽

Acclimation Response ◽

Gene Transcripts

Previous studies in our laboratory both in pine needles and potato leaves have shown evidence of an increase in 18: 2 (linoleate) in the purified plasma membrane fraction during cold acclimation. This increase was reversible on deacclimation, thereby suggesting a link between the accumulation of 18: 2 and acquisition of freezing tolerance. These studies suggest that the activity of specific desaturases may be modulated during cold acclimation. This study was aimed at studying the possible involvement of stearoyl-ACP desaturase (delta9) in potato cold acclimation response. Our approach was to study the induction of delta9 desaturase at the transcript level by using potato delta9 desaturase gene specific primers and reverse transcriptase. For this purpose, mRNA from S. tuberosum (cold sensitive, unable to acclimate) and S. commersonii (cold tolerant, able to cold acclimate) was extracted before and after acclimation. Sequence analysis confirmed that the amplified band was delta9 desaturase. Our results show that there is an increase in delta9 desaturase gene transcripts during cold acclimation and that this increase is associated with the cold acclimation response in potato. These results together with previous reports on the increase in 18: 2 in the plasma membrane during cold acclimation give more evidence toward the involvement of stearoyl-ACP desaturase (delta9) in the potato cold response.

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