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1.
Cell ; 162(6): 1242-56, 2015 Sep 10.
Article in English | MEDLINE | ID: mdl-26359984

ABSTRACT

Therapeutic antibodies targeting programmed cell death 1 (PD-1) activate tumor-specific immunity and have shown remarkable efficacy in the treatment of melanoma. Yet, little is known about tumor cell-intrinsic PD-1 pathway effects. Here, we show that murine and human melanomas contain PD-1-expressing cancer subpopulations and demonstrate that melanoma cell-intrinsic PD-1 promotes tumorigenesis, even in mice lacking adaptive immunity. PD-1 inhibition on melanoma cells by RNAi, blocking antibodies, or mutagenesis of melanoma-PD-1 signaling motifs suppresses tumor growth in immunocompetent, immunocompromised, and PD-1-deficient tumor graft recipient mice. Conversely, melanoma-specific PD-1 overexpression enhances tumorigenicity, as does engagement of melanoma-PD-1 by its ligand, PD-L1, whereas melanoma-PD-L1 inhibition or knockout of host-PD-L1 attenuate growth of PD-1-positive melanomas. Mechanistically, the melanoma-PD-1 receptor modulates downstream effectors of mTOR signaling. Our results identify melanoma cell-intrinsic functions of the PD-1:PD-L1 axis in tumor growth and suggest that blocking melanoma-PD-1 might contribute to the striking clinical efficacy of anti-PD-1 therapy.


Subject(s)
Melanoma/genetics , Programmed Cell Death 1 Receptor/metabolism , Signal Transduction , Animals , Antineoplastic Agents/administration & dosage , B7-H1 Antigen/genetics , Cell Line, Tumor , Cells, Cultured , Gene Knockdown Techniques , Heterografts , Humans , Mice , Mice, Inbred C57BL , Neoplasm Transplantation
2.
Plant Cell ; 2024 Apr 09.
Article in English | MEDLINE | ID: mdl-38593049

ABSTRACT

Phytochrome-interacting factors (PIFs) are basic helix-loop-helix transcription factors that regulate light responses downstream of phytochromes. In Arabidopsis (Arabidopsis thaliana), eight PIFs (PIF1-8) regulate light responses, either redundantly or distinctively. Distinctive roles of PIFs may be attributed to differences in mRNA expression patterns governed by promoters or variations in molecular activities of proteins. However, elements responsible for the functional diversification of PIFs have yet to be determined. Here, we investigated the role of promoters and proteins in the functional diversification of PIF1 and PIF4 by analyzing transgenic lines expressing promoter-swapped PIF1 and PIF4, as well as chimeric PIF1 and PIF4 proteins. For seed germination, PIF1 promoter played a major role, conferring dominance to PIF1 gene with a minor contribution from PIF1 protein. Conversely, for hypocotyl elongation under red light, PIF4 protein was the major element conferring dominance to PIF4 gene with the minor contribution from PIF4 promoter. In contrast, both PIF4 promoter and PIF4 protein were required for the dominant role of PIF4 in promoting hypocotyl elongation at high ambient temperatures. Together, our results support that the functional diversification of PIF1 and PIF4 genes resulted from contributions of both promoters and proteins, with their relative importance varying depending on specific light responses.

3.
Dermatol Surg ; 2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39074157

ABSTRACT

BACKGROUND: Minimally invasive cosmetic dermatology procedures continue to be increasingly popular; however, the extant literature has poorly documented the psychological antecedents of interest in cosmetic procedures and their psychological consequences. OBJECTIVE: To better inform dermatologists on their patients' motivations for cosmetic enhancement. MATERIALS AND METHODS: In a general population survey, an online representative sample of 984 Americans reported the extent to which they feel authentic using the validated authenticity scale and whether they were interested in undergoing a cosmetic procedure. In a prospective dermatology office survey, 102 participants reported their feelings of authenticity immediately before and 2 weeks after receiving a minimally invasive injectable cosmetic procedure. RESULTS: In the general population survey, participants interested in cosmetic procedures felt significantly less authentic than participants who were not interested (p = .003). In the prospective dermatology office survey, participants felt significantly more authentic 2 weeks after their minimally invasive injectable cosmetic procedure than before (p = .018). CONCLUSION: Lower feelings of authenticity are associated with interest in cosmetic procedures. Participants felt more authentic 2 weeks after receiving a minimally invasive injectable cosmetic procedure. Cosmetic procedures may present patients with an opportunity to feel more like their real, genuine selves.

4.
Mar Drugs ; 22(5)2024 May 13.
Article in English | MEDLINE | ID: mdl-38786608

ABSTRACT

We identified a new human voltage-gated potassium channel blocker, NnK-1, in the jellyfish Nemopilema nomurai based on its genomic information. The gene sequence encoding NnK-1 contains 5408 base pairs, with five introns and six exons. The coding sequence of the NnK-1 precursor is 894 nucleotides long and encodes 297 amino acids containing five presumptive ShK-like peptides. An electrophysiological assay demonstrated that the fifth peptide, NnK-1, which was chemically synthesized, is an effective blocker of hKv1.3, hKv1.4, and hKv1.5. Multiple-sequence alignment with cnidarian Shk-like peptides, which have Kv1.3-blocking activity, revealed that three residues (3Asp, 25Lys, and 34Thr) of NnK-1, together with six cysteine residues, were conserved. Therefore, we hypothesized that these three residues are crucial for the binding of the toxin to voltage-gated potassium channels. This notion was confirmed by an electrophysiological assay with a synthetic peptide (NnK-1 mu) where these three peptides were substituted with 3Glu, 25Arg, and 34Met. In conclusion, we successfully identified and characterized a new voltage-gated potassium channel blocker in jellyfish that interacts with three different voltage-gated potassium channels. A peptide that interacts with multiple voltage-gated potassium channels has many therapeutic applications in various physiological and pathophysiological contexts.


Subject(s)
Peptides , Potassium Channel Blockers , Potassium Channels, Voltage-Gated , Scyphozoa , Animals , Humans , Potassium Channel Blockers/pharmacology , Potassium Channel Blockers/chemistry , Potassium Channels, Voltage-Gated/antagonists & inhibitors , Peptides/pharmacology , Peptides/chemistry , Amino Acid Sequence , Cnidarian Venoms/pharmacology , Cnidarian Venoms/chemistry , Sequence Alignment
5.
J Integr Plant Biol ; 66(1): 103-120, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38088490

ABSTRACT

In order to flower in the appropriate season, plants monitor light and temperature changes and alter downstream pathways that regulate florigen genes such as Arabidopsis (Arabidopsis thaliana) FLOWERING LOCUS T (FT). In Arabidopsis, FT messenger RNA levels peak in the morning and evening under natural long-day conditions (LDs). However, the regulatory mechanisms governing morning FT induction remain poorly understood. The morning FT peak is absent in typical laboratory LDs characterized by high red:far-red light (R:FR) ratios and constant temperatures. Here, we demonstrate that ZEITLUPE (ZTL) interacts with the FT repressors TARGET OF EATs (TOEs), thereby repressing morning FT expression in natural environments. Under LDs with simulated sunlight (R:FR = 1.0) and daily temperature cycles, which are natural LD-mimicking environmental conditions, FT transcript levels in the ztl mutant were high specifically in the morning, a pattern that was mirrored in the toe1 toe2 double mutant. Low night-to-morning temperatures increased the inhibitory effect of ZTL on morning FT expression by increasing ZTL protein levels early in the morning. Far-red light counteracted ZTL activity by decreasing its abundance (possibly via phytochrome A (phyA)) while increasing GIGANTEA (GI) levels and negatively affecting the formation of the ZTL-GI complex in the morning. Therefore, the phyA-mediated high-irradiance response and GI play pivotal roles in morning FT induction. Our findings suggest that the delicate balance between low temperature-mediated ZTL activity and the far-red light-mediated functions of phyA and GI offers plants flexibility in fine-tuning their flowering time by controlling FT expression in the morning.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , Temperature , Red Light , Transcription Factors/metabolism , Flowers/physiology , Phytochrome A/metabolism , Gene Expression Regulation, Plant , Light , Mutation
6.
New Phytol ; 239(1): 208-221, 2023 07.
Article in English | MEDLINE | ID: mdl-37084001

ABSTRACT

In natural long days, the florigen gene FLOWERING LOCUS T (FT) shows a bimodal expression pattern with morning and dusk peaks in Arabidopsis. This pattern differs from the one observed in the laboratory, and little is known about underlying mechanisms. A red : far-red (R : FR) ratio difference between sunlight and fluorescent light causes this FT pattern mismatch. We showed that bimodal FT expression patterns were induced in a day longer than 14 h with sunlight R : FR (= c. 1) conditions. By circadian gating experiments, we found that cumulative exposure of R : FR-adjusted light (R : FR ratio was adjusted to 1 with FR supplement) spanning from the afternoon to the next morning required full induction of FT in the morning. Conversely, only 2 h of R : FR adjustment in the late afternoon was sufficient for FT induction at dusk. We identified that phytochrome A (phyA) is required for the morning FT expression in response to the R : FR adjustment on the previous day. As a part of this mechanism, we showed that PHYTOCHROME-INTERACTING FACTOR 7 contributes to FT regulation. Our results suggest that phyA-mediated high-irradiance response and the external coincidence mechanism contribute to morning FT induction under natural long-day conditions.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Light , Photoperiod , Flowers/genetics , Flowers/metabolism , Phytochrome A/metabolism , Gene Expression , Gene Expression Regulation, Plant
7.
J Drugs Dermatol ; 22(2): 210-216, 2023 Feb 01.
Article in English | MEDLINE | ID: mdl-36745365

ABSTRACT

Graham-Little Piccardi-Lasseur syndrome is a rare dermatosis that affects the hair follicles throughout the body and often presents with a progressive cicatricial alopecia of the scalp that is unresponsive to medical therapy. While treatment options are limited, prompt recognition through a careful physical exam aided by dermoscopy can facilitate early intervention. Here we present a patient with GLPLS, discuss pertinent morphologic and dermoscopic findings, and review the current literature. J Drugs Dermatol. 2022;22(2):210-216. doi:10.36849/JDD.6926.


Subject(s)
Alopecia , Lichen Planus , Humans , Syndrome , Alopecia/diagnosis , Alopecia/drug therapy , Cicatrix/pathology , Lichen Planus/drug therapy
8.
Sensors (Basel) ; 23(7)2023 Mar 25.
Article in English | MEDLINE | ID: mdl-37050511

ABSTRACT

In this study, we propose the direct diagnosis of thyroid cancer using a small probe. The probe can easily check the abnormalities of existing thyroid tissue without relying on experts, which reduces the cost of examining thyroid tissue and enables the initial self-examination of thyroid cancer with high accuracy. A multi-layer silicon-structured probe module is used to photograph light scattered by elastic changes in thyroid tissue under pressure to obtain a tactile image of the thyroid gland. In the thyroid tissue under pressure, light scatters to the outside depending on the presence of malignant and positive properties. A simple and easy-to-use tactile-sensation imaging system is developed by documenting the characteristics of the organization of tissues by using non-invasive technology for analyzing tactile images and judging the properties of abnormal tissues.


Subject(s)
Thyroid Neoplasms , Humans , Thyroid Neoplasms/diagnostic imaging , Touch , Diagnostic Imaging
9.
Facial Plast Surg ; 39(2): 180-184, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36075379

ABSTRACT

Nasal reconstruction has important functional and cosmetic considerations, as proper repair of nasal defects is necessary to maintain function of the nasal airway and to recreate the normal appearance of this central facial structure. Cheek advancement flaps provide matched, mobile, and highly vascularized tissue for the reconstruction of nasal defects, allowing for the concealment of incisions within natural creases in a one-stage approach. However, cheek advancement flaps are often underutilized for nasal reconstruction because of their difficulty in restoring nasal contour. We describe reconstruction of 19 nasal dorsal and sidewall defects 0.8 to 3 cm in size. We incorporated a periosteal anchoring suture to maintain/restore nasal contour and additionally removed a half standing cone inferior to the defect to prevent encroachment of the nasal ala or alar crease. All patients were evaluated at least 3 months postoperatively. In all patients, we were able to restore concavity of the nasofacial sulcus, preserve the biconvex nasal tips, prevent alar flaring and retraction, and conserve the alar groove. All patients had excellent functional and cosmetic outcomes. We believe this modified cheek advancement flap provides functionally and aesthetically superior results and can be considered as a first-line approach for repair of nasal dorsal and sidewall defects in subselected patients.


Subject(s)
Nose Neoplasms , Plastic Surgery Procedures , Humans , Cheek/surgery , Nose Neoplasms/surgery , Surgical Flaps , Nose/surgery
10.
Int J Dent Hyg ; 21(2): 438-449, 2023 May.
Article in English | MEDLINE | ID: mdl-36537784

ABSTRACT

OBJECTIVES: The aim of the study was to investigate patients with coronavirus disease 2019 (COVID-19) who visited dental clinics for treatment and to analyse the occurrence of additional COVID-19-confirmed cases according to the type of dental treatment and use of personal protective equipment (PPE). METHODS: Interviews were conducted in November 2021 via telephone, and written questionnaires were administered to dental hygienists working at the 24 dental clinics selected for the study, visited by patients with COVID-19. The survey focused on the visit date, the treatment received, whether or not the dental personnel wore PPE while treating the patient, and how the dental clinic and the public health centre with jurisdiction over the clinic responded after the patient's visit. RESULTS: Additional confirmed cases occurred in two of the 24 dental clinics included. In both cases, scaling was performed, dental personnel did not use a face shield, and patients with COVID-19 were asymptomatic. In 14 of the 22 dental clinics where additional confirmed cases did not occur, the dental personnel did not use face shields, and in 10 clinics, the dental personnel wore dental masks but not a KF94 mask. Based on these findings, which were obtained before the advent of the omicron variant, COVID-19 cross-infection did not appear to be high in dental clinics. CONCLUSION: The rate of COVID-19 cross-infection before the advent of the omicron variant appeared to be low in dental clinics in Korea. Therefore, patients have no reason to delay necessary dental treatment if dental personnel put effort into wearing PPE.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , SARS-CoV-2 , Dental Clinics , Republic of Korea/epidemiology
11.
Mar Drugs ; 19(3)2021 Mar 15.
Article in English | MEDLINE | ID: mdl-33804171

ABSTRACT

The proteolytic processing of amyloid precursor protein (APP) by ß-secretase (BACE1) and γ-secretase releases amyloid-ß peptide (Aß), which deposits in amyloid plaques and contributes to the initial causative events of Alzheimer's disease (AD). In the present study, the regulatory mechanism of APP processing of three phlorotannins was elucidated in Swedish mutant APP overexpressed N2a (SweAPP N2a) cells. Among the tested compounds, dieckol exhibited the highest inhibitory effect on both intra- and extracellular Aß accumulation. In addition, dieckol regulated the APP processing enzymes, such as α-secretase (ADAM10), ß-secretase, and γ-secretase, presenilin-1 (PS1), and their proteolytic products, sAPPα and sAPPß, implying that the compound acts on both the amyloidogenic and non-amyloidogenic pathways. In addition, dieckol increased the phosphorylation of protein kinase B (Akt) at Ser473 and GSK-3ß at Ser9, suggesting dieckol induced the activation of Akt, which phosphorylated GSK-3ß. The specific phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 triggered GSK-3ß activation and Aß expression. In addition, co-treatment with LY294002 noticeably blocked the effect of dieckol on Aß production, demonstrating that dieckol promoted the PI3K/Akt signaling pathway, which in turn inactivated GSK-3ß, resulting in the reduction in Aß levels.


Subject(s)
Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/metabolism , Benzofurans/pharmacology , Alzheimer Disease/drug therapy , Alzheimer Disease/physiopathology , Animals , Cell Line , Chromones/pharmacology , Glycogen Synthase Kinase 3 beta/metabolism , Mice , Morpholines/pharmacology , Phosphatidylinositol 3-Kinase/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction/drug effects , Tannins/pharmacology
12.
Ecotoxicol Environ Saf ; 227: 112931, 2021 Dec 20.
Article in English | MEDLINE | ID: mdl-34715500

ABSTRACT

Antidepressants are extensively used to treat the symptoms of depression in humans, and the environmentally discharged drugs potentially threaten aquatic organisms. In this study, the acute toxic effects of fluoxetine (FLX) were investigated in two aquatic organisms, the freshwater polyp (Hydra magnipapillata) and Javanese medaka (Oryzias javanicus). The median lethal concentration (LC50) of FLX in H. magnipapillata was 3.678, 3.082, and 2.901 mg/L after 24, 48, and 72 h, respectively. Morphological observations of the FLX-exposed H. magnipapillata showed that 1.5 mg/L FLX induced the contraction of the tentacles and body column. The LC50 of FLX in O. javanicus was 2.046, 1.936, 1.532, and 1.237 mg/L after 24, 48, 72, and 96 h, respectively. Observation of the behavior of the FLX-exposed fish showed that FLX reduced their swimming performance at a minimum concentration of 10 µg/L. The half-maximal effective concentration (EC50) of FLX for swimming behavior in O. javanicus was 0.135, 0.108, and 0.011 mg/L after 12, 24, and 96 h, respectively. Transcriptomic analyses indicated that FLX affects various physiological and metabolic processes in both species. FLX exposure induced oxidative stress, reproductive deficiency, abnormal pattern formation, DNA damage, and neurotransmission disturbance in H. magnipapillata, whereas it adversely affected O. javanicus by inducing oxidative stress, DNA damage, endoplasmic reticulum stress, and mRNA instability. Neurotransmission-based behavioral changes and endocrine disruption were strongly suspected in the FLX-exposed fish. These results suggest that FLX affects the behavior and metabolic regulation of aquatic organisms.


Subject(s)
Fluoxetine , Water Pollutants, Chemical , Animals , Antidepressive Agents , Endocrine System , Fluoxetine/toxicity , Humans , Synaptic Transmission , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity
13.
Dermatol Surg ; 46(10): 1300-1305, 2020 10.
Article in English | MEDLINE | ID: mdl-32028480

ABSTRACT

BACKGROUND: Electroabrasion, which uses an in-office electrosurgical device, is a method of surgical planning that ablates the skin to the papillary dermis. Several reports demonstrate that intraoperative ablative interventions with lasers or dermabrasion can modulate scar formation more effectively. This investigation uses electroabrasion intraoperatively to mitigate scar formation. OBJECTIVE: To evaluate the effectiveness of intraoperative electroabrasion for scar revision. MATERIALS AND METHODS: This was a prospective, randomized, observer-blinded, split-scar study with 24 linear scar segments resulting from primary closures in patients undergoing Mohs micrographic surgery. After placement of dermal sutures, half of the wound was randomly treated with electroabrasion. The other half was used as the control. Scar appearance was assessed by a blinded observer and by the patient using the Patient and Observer Scar Assessment Scale at 1 to 2 weeks, 1 month, and 3 months after surgery. RESULTS: At the 3-month follow-up, both patient and observer variables measuring scar contour improved on the treated side, whereas erythema was worse. Overall, no difference was seen in total scores between the 2 sides. CONCLUSION: Based on this pilot study, scars treated with electroabrasion revealed improved surface topography but worsened erythema. Future studies with more refined electrosurgical settings are needed for further evaluation.


Subject(s)
Cicatrix/prevention & control , Dermabrasion/methods , Electrocoagulation/methods , Intraoperative Care/methods , Mohs Surgery/adverse effects , Aged , Cicatrix/diagnosis , Cicatrix/etiology , Dermabrasion/adverse effects , Dermabrasion/instrumentation , Electrocoagulation/adverse effects , Electrocoagulation/instrumentation , Female , Follow-Up Studies , Humans , Intraoperative Care/adverse effects , Intraoperative Care/instrumentation , Male , Middle Aged , Pilot Projects , Prospective Studies , Severity of Illness Index , Treatment Outcome
14.
BMC Biol ; 17(1): 28, 2019 03 29.
Article in English | MEDLINE | ID: mdl-30925871

ABSTRACT

BACKGROUND: Unique among cnidarians, jellyfish have remarkable morphological and biochemical innovations that allow them to actively hunt in the water column and were some of the first animals to become free-swimming. The class Scyphozoa, or true jellyfish, are characterized by a predominant medusa life-stage consisting of a bell and venomous tentacles used for hunting and defense, as well as using pulsed jet propulsion for mobility. Here, we present the genome of the giant Nomura's jellyfish (Nemopilema nomurai) to understand the genetic basis of these key innovations. RESULTS: We sequenced the genome and transcriptomes of the bell and tentacles of the giant Nomura's jellyfish as well as transcriptomes across tissues and developmental stages of the Sanderia malayensis jellyfish. Analyses of the Nemopilema and other cnidarian genomes revealed adaptations associated with swimming, marked by codon bias in muscle contraction and expansion of neurotransmitter genes, along with expanded Myosin type II family and venom domains, possibly contributing to jellyfish mobility and active predation. We also identified gene family expansions of Wnt and posterior Hox genes and discovered the important role of retinoic acid signaling in this ancient lineage of metazoans, which together may be related to the unique jellyfish body plan (medusa formation). CONCLUSIONS: Taken together, the Nemopilema jellyfish genome and transcriptomes genetically confirm their unique morphological and physiological traits, which may have contributed to the success of jellyfish as early multi-cellular predators.


Subject(s)
Evolution, Molecular , Genome/physiology , Predatory Behavior , Scyphozoa/physiology , Animals , Biological Evolution , Phylogeny , Scyphozoa/genetics
15.
Molecules ; 25(21)2020 Nov 02.
Article in English | MEDLINE | ID: mdl-33147823

ABSTRACT

Amyloid beta (Aß) peptide, one of the most important pathogenic traits of Alzheimer's disease (AD), invokes a cascade of oxidative damage and eventually leads to neuronal death. In the present study, baicalein, wogonin, and oroxylin A, main active flavones in Scutellaria baicalensis, were evaluated for their neuroprotective effects against Aß25-35-stimulated damage. All tested compounds decreased Aß25-35-induced ROS generation and cell cycle arrest. In particular, baicalein exhibited the strongest antioxidant activity. In addition, these compounds suppressed apoptosis by attenuating mitochondrial dysfunction such as loss of membrane potential, Ca2+ accumulation and Bax/Bcl-2 ratio. Furthermore, all tested flavones inhibited the expression of iNOS and COX-2, which resulted in suppressing inflammatory cytokines including TNF-α, NO, and PGE2. Noticeably, all compounds exhibited the anti-inflammatory effects through downregulating NF-κB/MAPK pathway. Especially, oroxylin A was effective against both p65 and IκBα, while wogonin and baicalein were suppressed phospho-p65 and phospho-IκBα, respectively. Taken together, baicalein, wogonin, and oroxylin A can effectively relieve Aß25-35-stimulated neuronal apoptosis and inflammation in PC12 cells via downregulating NF-κB/MAPK signaling pathway.


Subject(s)
Alzheimer Disease , Amyloid beta-Peptides/metabolism , Flavanones/pharmacology , Flavonoids/pharmacology , MAP Kinase Signaling System/drug effects , Peptide Fragments/metabolism , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Animals , Extracellular Signal-Regulated MAP Kinases/metabolism , NF-kappa B/metabolism , PC12 Cells , Rats
16.
Proteomics ; 19(17): e1900086, 2019 09.
Article in English | MEDLINE | ID: mdl-31318149

ABSTRACT

Mitogen-activated protein (MAP) kinase signaling is critical for various cellular responses, including cell proliferation, differentiation, and cell death. The MAP kinase cascade is conserved in the eukaryotic kingdom as a three-tiered kinase module-MAP kinase kinase kinase, MAP kinase kinase, and MAP kinase-that transduces signals via sequential phosphorylation upon stimulation. Dual phosphorylation of MAP kinase on the conserved threonine-glutamic acid-tyrosine (TEY) motif is essential for its catalytic activity and signal activation; however, the molecular mechanism by which the two residues are phosphorylated remains elusive. In the present study, the pattern of dual phosphorylation of extracellular signal-regulated kinase (ERK) is profiled on the TEY motif using stable isotope dilution (SID)-selective reaction monitoring (SRM) mass spectrometry (MS) to elucidate the order and magnitude of endogenous ERK phosphorylation in cellular model systems. The SID-SRM-MS analysis of phosphopeptides demonstrates that tyrosine phosphorylation in the TEY motif is dynamic, while threonine phosphorylation is static. Analyses of the mono-phosphorylatable mutants ERKT202A and ERKY204F indicate that phosphorylation of tyrosine is not affected by the phosphorylation state of threonine, while threonine phosphorylation depends on tyrosine phosphorylation. The data suggest that dual phosphorylation of ERK is a highly ordered and restricted mechanism determined by tyrosine phosphorylation.


Subject(s)
Extracellular Signal-Regulated MAP Kinases/metabolism , Glutamic Acid/metabolism , Mitogen-Activated Protein Kinase Kinases/metabolism , Threonine/metabolism , Tyrosine/metabolism , Animals , Extracellular Signal-Regulated MAP Kinases/chemistry , Extracellular Signal-Regulated MAP Kinases/genetics , Glutamic Acid/chemistry , Glutamic Acid/genetics , HeLa Cells , Humans , Mitogen-Activated Protein Kinase Kinases/chemistry , Mitogen-Activated Protein Kinase Kinases/genetics , Mutation , PC12 Cells , Phosphorylation , Rats , Signal Transduction , Threonine/chemistry , Threonine/genetics , Tyrosine/chemistry , Tyrosine/genetics
17.
Plant Cell ; 28(6): 1388-405, 2016 06.
Article in English | MEDLINE | ID: mdl-27303023

ABSTRACT

The bHLH transcription factor PHYTOCHROME INTERACTING FACTOR1 (PIF1) binds G-box elements in vitro and inhibits light-dependent germination in Arabidopsis thaliana A previous genome-wide analysis of PIF1 targeting indicated that PIF1 binds 748 sites in imbibed seeds, only 59% of which possess G-box elements. This suggests the G-box is not the sole determinant of PIF1 targeting. The targeting of PIF1 to specific sites could be stabilized by PIF1-interacting transcription factors (PTFs) that bind other nearby sequence elements. Here, we report PIF1 targeting sites are enriched with not only G-boxes but also with other hexameric sequence elements we named G-box coupling elements (GCEs). One of these GCEs possesses an ACGT core and serves as a binding site for group A bZIP transcription factors, including ABSCISIC ACID INSENSITIVE5 (ABI5), which inhibits seed germination in abscisic acid signaling. PIF1 interacts with ABI5 and other group A bZIP transcription factors and together they target a subset of PIF1 binding sites in vivo. In vitro single-molecule fluorescence imaging confirms that ABI5 facilitates PIF1 binding to DNA fragments possessing multiple G-boxes or the GCE alone. Thus, we show in vivo PIF1 targeting to specific binding sites is determined by its interaction with PTFs and their binding to GCEs.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Basic Helix-Loop-Helix Transcription Factors/metabolism , Transcription Factors/metabolism , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic-Leucine Zipper Transcription Factors/genetics , Basic-Leucine Zipper Transcription Factors/metabolism , Binding Sites/genetics , Binding Sites/physiology , Gene Expression Regulation, Plant/genetics , Gene Expression Regulation, Plant/physiology , Protein Binding/genetics , Protein Binding/physiology , Transcription Factors/genetics
20.
J Exp Bot ; 69(10): 2511-2525, 2018 04 27.
Article in English | MEDLINE | ID: mdl-29514290

ABSTRACT

Ethylene is a phytohormone involved in the regulation of several aspects of plant development and in responses to biotic and abiotic stress. The effects of exogenous application of ethylene to sugarcane plants are well characterized as growth inhibition of immature internodes and stimulation of sucrose accumulation. However, the molecular network underlying the control of ethylene biosynthesis in sugarcane remains largely unknown. The chemical reaction catalyzed by 1-aminocyclopropane-1-carboxylic acid synthase (ACS) is an important rate-limiting step that regulates ethylene production in plants. In this work, using a yeast one-hybrid approach, we identified three basic helix-loop-helix (bHLH) transcription factors, homologs of Arabidopsis FBH (FLOWERING BHLH), that bind to the promoter of ScACS2 (Sugarcane ACS2), a sugarcane type 3 ACS isozyme gene. Protein-protein interaction assays showed that sugarcane FBH1 (ScFBH1), ScFBH2, and ScFBH3 form homo- and heterodimers in the nucleus. Gene expression analysis revealed that ScFBHs and ScACS2 transcripts are more abundant in maturing internodes during afternoon and night. In addition, Arabidopsis functional analysis demonstrated that FBH controls ethylene production by regulating transcript levels of ACS7, a homolog of ScACS2. These results indicate that ScFBHs transcriptionally regulate ethylene biosynthesis in maturing internodes of sugarcane.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/genetics , Ethylenes/metabolism , Gene Expression Regulation, Plant/genetics , Lyases/genetics , Plant Growth Regulators/metabolism , Plant Proteins/genetics , Saccharum/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , Isoenzymes/metabolism , Lyases/metabolism , Plant Proteins/metabolism , Plants, Genetically Modified/enzymology , Plants, Genetically Modified/genetics , Plants, Genetically Modified/metabolism , Promoter Regions, Genetic , Saccharum/enzymology , Saccharum/metabolism
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