scholarly journals PCH1 regulates light, temperature, and circadian signaling as a structural component of phytochrome B-photobodies in Arabidopsis

2019 ◽  
Author(s):  
He Huang ◽  
Katrice E. McLoughlin ◽  
Maria L. Sorkin ◽  
E. Sethe Burgie ◽  
Rebecca K. Bindbeutel ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Structural Component ◽  
Genetic Interaction ◽  
Red Light ◽  
Early Event ◽  
Plant Responses ◽  
Phytochrome B ◽  
Thermal Perception ◽  
Interacting Protein

AbstractThe phytochrome (phy) family of bilin-containing photoreceptors are major regulators of plant photomorphogenesis through their unique ability to photointerconvert between a biologically inactive red light-absorbing Pr state and an active far-red light­absorbing Pfr state. While the initial steps in Pfr signaling are unclear, an early event for the phyB isoform after photoconversion is its redistribution from the cytoplasm into subnuclear foci named photobodies (PBs) that dissipate after Pfr reverts back to Pr by far-red irradiation or by temperature-dependent non-photochemical reversion. Here we present evidence that PHOTOPERIODIC CONTROL OF HYPOCOTYL 1 (PCH1) functions both as an essential structural component of phyB-containing PBs and as a direct regulator of thermal reversion that is sufficient to stabilize phyB as Pfr in vitro. By examining the genetic interaction between a constitutively active phyBY276H-YFP allele (YHB-YFP) and PCH1, we show that the loss of PCH1 prevents YHB from coalescing into PBs without affecting its nuclear localization, whereas overexpression of PCH1 dramatically increases PB levels. Loss of PCH1, presumably by impacting phyB-PB assembly, compromises a number of events elicited in YHB-YFP plants, including their constitutive photomorphogenic phenotype, red light-regulated thermomorphogenesis, and input of phyB into the circadian clock. Conversely, elevated levels of both phyB and PCH1 generate stable, yet far red-light reversible PBs that persisted for days. Collectively, our data demonstrate that the assembly of PCHl-containing PBs is critical for phyB signaling to multiple outputs, and suggest that altering PB dynamics could be exploited to modulate plant responses to light and temperature.SignificanceIn Arabidopsis, phytochrome B (phyB) perceives light and temperature signals to regulate various fundamental morphogenic processes in plants through its interconversion between its active Pfr and inactive Pr states. Upon photoconversion from Pr to Pfr, phyB forms subnuclear foci called photobodies, whose composition and molecular function(s) are unclear. We show here that the phyB-interacting protein PCH1 is a structural component of phyB-photobodies and protects Pfr from thermal reversion back to Pr thus helping maintain phyB signaling. Loss of PCH1 compromises photobody formation, which disrupts a number of downstream events including photo- and thermal perception and signaling into the circadian clock. These results demonstrate that forming PCHl-dependent phyB-photobodies is an essential step connecting light and temperature to controls on plant morphogenesis.

scholarly journals PCH1 regulates light, temperature, and circadian signaling as a structural component of phytochrome B-photobodies inArabidopsis

2019 ◽  
Vol 116 (17) ◽  
pp. 8603-8608 ◽  
Author(s):  
He Huang ◽  
Katrice E. McLoughlin ◽  
Maria L. Sorkin ◽  
E. Sethe Burgie ◽  
Rebecca K. Bindbeutel ◽  
...  
Keyword(s):  
Structural Component ◽  
Genetic Interaction ◽  
Red Light ◽  
Early Event ◽  
Plant Responses ◽  
Phytochrome B ◽  
Temperature Dependent ◽  
Direct Regulator ◽  
Unique Ability

The members of the phytochrome (phy) family of bilin-containing photoreceptors are major regulators of plant photomorphogenesis through their unique ability to photointerconvert between a biologically inactive red light-absorbing Pr state and an active far-red light-absorbing Pfr state. While the initial steps in Pfr signaling are unclear, an early event for the phyB isoform after photoconversion is its redistribution from the cytoplasm into subnuclear foci known as photobodies (PBs), which dissipate after Pfr reverts back to Pr by far-red irradiation or by temperature-dependent nonphotochemical reversion. Here we present evidence that PHOTOPERIODIC CONTROL OF HYPOCOTYL 1 (PCH1) functions both as an essential structural component of phyB-containing PBs and as a direct regulator of thermal reversion that is sufficient to stabilize phyB as Pfr in vitro. By examining the genetic interaction between a constitutively active phyBY276H-YFP allele (YHB-YFP) and PCH1, we show that the loss of PCH1 prevents YHB from coalescing into PBs without affecting its nuclear localization, whereas overexpression of PCH1 dramatically increases PB levels. Loss of PCH1, presumably by impacting phyB-PB assembly, compromises a number of events elicited inYHB-YFPplants, including their constitutive photomorphogenic phenotype, red light-regulated thermomorphogenesis, and input of phyB into the circadian clock. Conversely, elevated levels of both phyB and PCH1 generate stable, yet far-red light–reversible PBs that persisted for days. Collectively, our data demonstrate that the assembly of PCH1-containing PBs is critical for phyB signaling to multiple outputs and suggest that altering PB dynamics could be exploited to modulate plant responses to light and temperature.

Abstract 259: KChIP2 is a Key Transcriptional Regulator of Cardiac Excitability Under Normal and Pathogenic Conditions

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Drew M Nassal ◽  
Xiaoping Wan ◽  
Haiyan Liu ◽  
Danielle Maleski ◽  
Angelina Ramirez-Navarro ◽  
...  
Keyword(s):  
Heart Disease ◽  
Ventricular Myocytes ◽  
Direct Interaction ◽  
Neonatal Rat ◽  
K Channel ◽  
Early Event ◽  
Interacting Protein ◽  
Protein Levels ◽  
Cardiac Excitability

Introduction: Arrhythmogenesis is the primary cause of death in patients with acquired heart disease, and is the consequence of profound dysregulation of both depolarizing and repolarizing currents. Reduction in expression of the auxiliary subunit K+ channel interacting protein 2 (KChIP2), which regulates the transient outward K+ current (Ito), is a common and early event in many cardiac pathologies. Notably, transcriptional changes observed in heart disease can be elicited through direct KChIP2 silencing without disease signaling, suggesting novel transcriptional capacity for KChIP2. Methods and Results: A miRNA microarray was conducted on neonatal rat ventricular myocytes (NRVM) following in vitro silencing of KChIP2, identifying the miR-34 family as a potential transcriptional target of KChIP2. qPCR confirmed reduction in miR-34b/c when over-expressing KChIP2 and increase following silencing. Luciferase assays conducted on the promoter for miR-34b/c reinforced KChIP2 repression on the promoter, while chromatin immunoprecipitation identified direct interaction of KChIP2 on the promoter. Previous studies show modified expression of KChIP2 can lead to changes in several ion channel subunits. Therefore, we investigated if this was the consequence of KChIP2 regulation via miR-34. Expression of miR-34b/c precursors reduced transcript levels of Nav1.5 and Navβ1, and reduced protein levels for Kv4.3, resulting in loss of INa and Ito. To determine the relevance in disease signaling, NRVMs were exposed to 100 μM phenylephrine for 48 hrs, significantly reducing KChIP2, Nav1.5, Navβ1, and Kv4.3, while elevating miR-34b/c. Maintaining KChIP2 expression by adenovirus or blocking miR-34 activity with antagomirs rescued the changes in channel expression. Consequently, miR-34 inhibition rescued the induction of sustained arrhythmias observed in a 2D culture of myocytes through the maintenance of cardiac excitability. Conclusion: Collectively, these observations identify dysregulation of the KChIP2/miR-34 axis as a nodal event in the development of electrical dysfunction that characterize cardiac pathologies, and further identifies miR-34 as a viable therapeutic target for managing arrhythmogenesis in patients with heart disease.

scholarly journals A role for Yip1p in COPII vesicle biogenesis

2003 ◽  
Vol 163 (1) ◽  
pp. 57-69 ◽  
Author(s):  
Matthew Heidtman ◽  
Catherine Z. Chen ◽  
Ruth N. Collins ◽  
Charles Barlowe
Keyword(s):  
Secretory Pathway ◽  
Protein Transport ◽  
Genetic Interaction ◽  
Temperature Sensitive ◽  
Rab Gtpases ◽  
Direct Role ◽  
Interacting Protein ◽  
Copii Vesicle ◽  
Vesicle Biogenesis

Yeast Ypt1p-interacting protein (Yip1p) belongs to a conserved family of transmembrane proteins that interact with Rab GTPases. We encountered Yip1p as a constituent of ER-derived transport vesicles, leading us to hypothesize a direct role for this protein in transport through the early secretory pathway. Using a cell-free assay that recapitulates protein transport from the ER to the Golgi complex, we find that affinity-purified antibodies directed against the hydrophilic amino terminus of Yip1p potently inhibit transport. Surprisingly, inhibition is specific to the COPII-dependent budding stage. In support of this in vitro observation, strains bearing the temperature-sensitive yip1-4 allele accumulate ER membranes at a nonpermissive temperature, with no apparent accumulation of vesicle intermediates. Genetic interaction analyses of the yip1-4 mutation corroborate a function in ER budding. Finally, ordering experiments show that preincubation of ER membranes with COPII proteins decreases sensitivity to anti-Yip1p antibodies, indicating an early requirement for Yip1p in vesicle formation. We propose that Yip1p has a previously unappreciated role in COPII vesicle biogenesis.

scholarly journals SUMOylation of phytochrome-B negatively regulates light-induced signaling in Arabidopsis thaliana

2015 ◽  
Vol 112 (35) ◽  
pp. 11108-11113 ◽  
Author(s):  
Ari Sadanandom ◽  
Éva Ádám ◽  
Beatriz Orosa ◽  
András Viczián ◽  
Cornelia Klose ◽  
...  
Keyword(s):  
Molecular Level ◽  
Expression Patterns ◽  
Red Light ◽  
Regulatory Proteins ◽  
Light Signaling ◽  
Phytochrome B ◽  
Sumo Proteases ◽  
C Terminus

The red/far red light absorbing photoreceptor phytochrome-B (phyB) cycles between the biologically inactive (Pr, λmax, 660 nm) and active (Pfr; λmax, 730 nm) forms and functions as a light quality and quantity controlled switch to regulate photomorphogenesis in Arabidopsis. At the molecular level, phyB interacts in a conformation-dependent fashion with a battery of downstream regulatory proteins, including PHYTOCHROME INTERACTING FACTOR transcription factors, and by modulating their activity/abundance, it alters expression patterns of genes underlying photomorphogenesis. Here we report that the small ubiquitin-like modifier (SUMO) is conjugated (SUMOylation) to the C terminus of phyB; the accumulation of SUMOylated phyB is enhanced by red light and displays a diurnal pattern in plants grown under light/dark cycles. Our data demonstrate that (i) transgenic plants expressing the mutant phyBLys996Arg-YFP photoreceptor are hypersensitive to red light, (ii) light-induced SUMOylation of the mutant phyB is drastically decreased compared with phyB-YFP, and (iii) SUMOylation of phyB inhibits binding of PHYTOCHROME INTERACTING FACTOR 5 to phyB Pfr. In addition, we show that OVERLY TOLERANT TO SALT 1 (OTS1) de-SUMOylates phyB in vitro, it interacts with phyB in vivo, and the ots1/ots2 mutant is hyposensitive to red light. Taken together, we conclude that SUMOylation of phyB negatively regulates light signaling and it is mediated, at least partly, by the action of OTS SUMO proteases.

scholarly journals Saccharomyces cerevisiae RAI1 (YGL246c) Is Homologous to Human DOM3Z and Encodes a Protein That Binds the Nuclear Exoribonuclease Rat1p

2000 ◽  
Vol 20 (11) ◽  
pp. 4006-4015 ◽  
Author(s):  
Yang Xue ◽  
Xinxue Bai ◽  
Insuk Lee ◽  
George Kallstrom ◽  
Jennifer Ho ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Genetic Interaction ◽  
Rna Degradation ◽  
Growth Defect ◽  
Nuclear Targeting ◽  
Interacting Protein ◽  
Rrna Species ◽  
Synthetically Lethal

ABSTRACT The RAT1 gene of Saccharomyces cerevisiaeencodes a 5′→3′ exoribonuclease which plays an essential role in yeast RNA degradation and/or processing in the nucleus. We have cloned a previously uncharacterized gene (YGL246c) that we refer to asRAI1 (Rat1p interacting protein 1). RAI1 is homologous to Caenorhabditis elegans DOM-3 and humanDOM3Z. Deletion of RAI1 confers a growth defect which can be complemented by an additional copy of RAT1 on a centromeric vector or by directing Xrn1p, the cytoplasmic homolog of Rat1p, to the nucleus through the addition of a nuclear targeting sequence. Deletion of RAI1 is synthetically lethal with therat1-1ts mutation and shows genetic interaction with a deletion of SKI2 but not XRN1. Polysome analysis of an rai1 deletion mutant indicated a defect in 60S biogenesis which was nearly fully reversed by high-copyRAT1. Northern blot analysis of rRNAs revealed thatrai1 is required for normal 5.8S processing. In the absence of RAI1, 5.8SL was the predominant form of 5.8S and there was an accumulation of 3′-extended forms but not 5′-extended species of 5.8S. In addition, a 27S pre-rRNA species accumulated in therai1 mutant. Thus, deletion of RAI1 affects both 5′ and 3′ processing reactions of 5.8S rRNA. Consistent with the in vivo data suggesting that RAI1 enhances RAT1function, purified Rai1p stabilized the in vitro exoribonuclease activity of Rat1p.

scholarly journals BLADE-ON-PETIOLE proteins act in an E3 ubiquitin ligase complex to regulate PHYTOCHROME INTERACTING FACTOR 4 abundance

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Bo Zhang ◽  
Mattias Holmlund ◽  
Severine Lorrain ◽  
Mikael Norberg ◽  
László Bakó ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Flower Development ◽  
Red Light ◽  
E3 Ubiquitin Ligase ◽  
Plant Responses ◽  
Signaling Mechanism ◽  
Ubiquitin Ligase Complex ◽  
Molecular Determinants ◽  
Subsequent Degradation

Both light and temperature have dramatic effects on plant development. Phytochrome photoreceptors regulate plant responses to the environment in large part by controlling the abundance of PHYTOCHROME INTERACTING FACTOR (PIF) transcription factors. However, the molecular determinants of this essential signaling mechanism still remain largely unknown. Here, we present evidence that the BLADE-ON-PETIOLE (BOP) genes, which have previously been shown to control leaf and flower development in Arabidopsis, are involved in controlling the abundance of PIF4. Genetic analysis shows that BOP2 promotes photo-morphogenesis and modulates thermomorphogenesis by suppressing PIF4 activity, through a reduction in PIF4 protein level. In red-light-grown seedlings PIF4 ubiquitination was reduced in the bop2 mutant. Moreover, we found that BOP proteins physically interact with both PIF4 and CULLIN3A and that a CULLIN3-BOP2 complex ubiquitinates PIF4 in vitro. This shows that BOP proteins act as substrate adaptors in a CUL3BOP1/BOP2 E3 ubiquitin ligase complex, targeting PIF4 proteins for ubiquitination and subsequent degradation.

The homeodomain-leucine zipper ATHB23, a phytochrome B-interacting protein, is important for phytochrome B-mediated red light signaling

2013 ◽  
Vol 150 (2) ◽  
pp. 308-320 ◽  
Author(s):  
Hyunmo Choi ◽  
Suyeong Jeong ◽  
Dong Su Kim ◽  
Hyung Jin Na ◽  
Jong Sang Ryu ◽  
...  
Keyword(s):  
Leucine Zipper ◽  
Red Light ◽  
Light Signaling ◽  
Phytochrome B ◽  
Interacting Protein

scholarly journals Neighbor signals perceived by phytochrome B increase thermotolerance in Arabidopsis

2018 ◽  
Author(s):  
Denise Arico ◽  
Martina Legris ◽  
Luciana Castro ◽  
Carlos Fernando Garcia ◽  
Aldana Laino ◽  
...  
Keyword(s):  
Heat Stress ◽  
Unsaturated Fatty Acids ◽  
Red Light ◽  
Fatty Acid Desaturase ◽  
Tissue Temperature ◽  
Plant Responses ◽  
Phytochrome B ◽  
Simulated Sunlight ◽  
Quality Signals ◽  
Heat Shocks

AbstractDue to the preeminence of reductionist approaches, our understanding of plant responses to combined stresses is limited. We speculated that light-quality signals of neighboring vegetation might increase susceptibility to heat shocks because shade reduces tissue temperature and hence the likeness of heat shocks. In contrast, plants of Arabidopsis thaliana grown under low red / far-red ratios typical of shade were less damaged by heat stress than plants grown under simulated sunlight. Shade reduces the activity of phytochrome B (phyB) and the phyB mutant showed high tolerance to heat stress even under simulated sunlight. The enhanced heat tolerance under low red / far-red ratios failed in a multiple mutant of PHYTOCHROME INTERACTING FACTORs. The phyB mutant showed reduced expression of several fatty acid desaturase (FAD) genes, proportion of fully unsaturated fatty acids and electrolyte leakage of membranes exposed to a heat shock. Activation of phyB by red light also reduced thermotolerance of dark-grown (etiolated) seedlings but not via changes in FAD gene expression and membrane stability. We propose that the reduced photosynthetic capacity linked to thermotolerant membranes would be less costly under shade, where the light input itself limits photosynthesis.

scholarly journals Generation of High-Yield, Functional Oligodendrocytes from a c-myc Immortalized Neural Cell Line, Endowed with Staminal Properties

2021 ◽  
Vol 22 (3) ◽  
pp. 1124
Author(s):  
Mafalda Giovanna Reccia ◽  
Floriana Volpicelli ◽  
Eirkiur Benedikz ◽  
Åsa Fex Svenningsen ◽  
Luca Colucci-D’Amato
Keyword(s):  
Cell Line ◽  
Low Cost ◽  
Neural Cell ◽  
New Drugs ◽  
High Yield ◽  
Time Saving ◽  
Interacting Protein ◽  
Neuronal Marker ◽  
Differentiation Status

Neural stem cells represent a powerful tool to study molecules involved in pathophysiology of Nervous System and to discover new drugs. Although they can be cultured and expanded in vitro as a primary culture, their use is hampered by their heterogeneity and by the cost and time needed for their preparation. Here we report that mes-c-myc A1 cells (A1), a neural cell line, is endowed with staminal properties. Undifferentiated/proliferating and differentiated/non-proliferating A1 cells are able to generate neurospheres (Ns) in which gene expression parallels the original differentiation status. In fact, Ns derived from undifferentiated A1 cells express higher levels of Nestin, Kruppel-like factor 4 (Klf4) and glial fibrillary protein (GFAP), markers of stemness, while those obtained from differentiated A1 cells show higher levels of the neuronal marker beta III tubulin. Interestingly, Ns differentiation, by Epidermal Growth Factors (EGF) and Fibroblast Growth Factor 2 (bFGF) withdrawal, generates oligodendrocytes at high-yield as shown by the expression of markers, Galactosylceramidase (Gal-C) Neuron-Glial antigen 2 (NG2), Receptor-Interacting Protein (RIP) and Myelin Basic Protein (MBP). Finally, upon co-culture, Ns-A1-derived oligodendrocytes cause a redistribution of contactin-associated protein (Caspr/paranodin) protein on neuronal cells, as primary oligodendrocytes cultures, suggesting that they are able to form compact myelin. Thus, Ns-A1-derived oligodendrocytes may represent a time-saving and low-cost tool to study the pathophysiology of oligodendrocytes and to test new drugs.

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