scholarly journals The seven transmembrane domain protein MoRgs7 functions in surface perception and undergoes coronin MoCrn1-dependent endocytosis in complex with Gα subunit MoMagA to promote cAMP signaling and appressorium formation in Magnaporthe oryzae

2019 ◽  
Vol 15 (2) ◽  
pp. e1007382 ◽  
Author(s):  
Xiao Li ◽  
Kaili Zhong ◽  
Ziyi Yin ◽  
Jiexiong Hu ◽  
Wenhao Wang ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Transmembrane Domain ◽  
Camp Signaling ◽  
Appressorium Formation ◽  
Surface Perception ◽  
Domain Protein

scholarly journals The seven transmembrane domain protein MoRgs7 functions in surface perception and undergoes coronin MoCrn1-dependent endocytosis in complex with Gα subunit MoMagA to promote cAMP signaling and appressorium formation in Magnaporthe oryzae

2018 ◽  
Author(s):  
Xiao Li ◽  
Kaili Zhong ◽  
Ziyi Yin ◽  
Jiexiong Hu ◽  
Lianwei Li ◽  
...  
Keyword(s):  
G Protein ◽  
Magnaporthe Oryzae ◽  
Transmembrane Domain ◽  
Surface Hydrophobicity ◽  
Camp Signaling ◽  
Actin Binding ◽  
Rgs Proteins ◽  
Appressorium Formation ◽  
Rgs Domain ◽  
Tm Domain

AbstractRegulator of G-protein signaling (RGS) proteins primarily function as GTPase-accelerating proteins (GAPs) to promote GTP hydrolysis of Gα subunits, thereby regulating G-protein mediated signaling. RGS proteins could also contain additional domains such as GoLoco to inhibit GDP dissociation. The rice blast fungus Magnaporthe oryzae encodes eight RGS and RGS-like proteins (MoRgs1 to MoRgs8) that have shared and distinct functions in growth, appressorium formation and pathogenicity. Interestingly, MoRgs7 and MoRgs8 contain a C-terminal seven-transmembrane domain (7-TM) motif typical of G-protein coupled receptor (GPCR) proteins, in addition to the conserved RGS domain. We found that MoRgs7, together with Gα MoMagA but not MoRgs8, undergoes endocytic transport from the plasma membrane to the endosome upon sensing of surface hydrophobicity. We also found that MoRgs7 can interact with hydrophobic surfaces via a hydrophobic interaction, leading to the perception of environmental hydrophobic cues. Moreover, we found that MoRgs7-MoMagA endocytosis is regulated by actin patch-associated protein MoCrn1, linking it to cAMP signaling. Our studies provided evidence suggesting that MoRgs7 could also function in a GPCR-like manner to sense environmental signals and it, together with additional proteins of diverse functions, promotes cAMP signaling required for developmental processes underlying appressorium function and pathogenicity.Author summaryThe 7-TM domain is considered the hallmark of GPCR proteins, which activate G proteins upon ligand binding and undergo endocytosis for regeneration or recycling. Among eight RGS and RGS-like proteins of M. oryzae, MoRgs7 and MoRgs8 contain the 7-TM domain in addition to the RGS domain. We found that MoRgs7 can form hydrophobic interactions with the hydrophobic surface. This interaction is important in sensing hydrophobic cues by the fungus. We also found that, in response to surface hydrophobicity, MoRgs7 couples with Gα subunit MoMagA to undergo endocytosis leading to the activation of cAMP signaling. Moreover, we found that such an endocytic event requires functions of the actin-binding protein MoCrn1. Our results revealed MoRgs7 functions as a GPCR-like receptor protein to sense surface cues and activate signaling required for pathogenesis, providing new insights into G-protein regulatory mechanisms in this and other pathogenic fungi.

scholarly journals Pleiotropic functions of the transmembrane domain 6 of human melanocortin-4 receptor

2012 ◽  
Vol 49 (3) ◽  
pp. 237-248 ◽  
Author(s):  
Hui Huang ◽  
Ya-Xiong Tao
Keyword(s):  
Cell Surface ◽  
Structure Function ◽  
Transmembrane Domain ◽  
Mapk Pathway ◽  
Surface Expression ◽  
Camp Signaling ◽  
Cell Surface Expression ◽  
Melanocortin 4 Receptor ◽  
Function Relationship ◽  
Relationship Of

The melanocortin-4 receptor (MC4R) is a critical regulator of energy homeostasis and has emerged as a premier target for obesity treatment. Numerous mutations in transmembrane domain 6 (TM6) of MC4R resulting in functional alterations have been identified in obese patients. Several mutagenesis studies also provided some data suggesting the importance of this domain in receptor function. To gain a better understanding of the structure–function relationship of the receptor, we performed alanine-scanning mutagenesis in TM6 to determine the functions of side chains. Of the 31 residues, two were important for cell surface expression, five were indispensable for α-melanocyte-stimulating hormone (α-MSH) and β-MSH binding, and six were important for signaling in the Gs–cAMP–PKA pathway. H264A, targeted normally to the plasma membrane, was undetectable by competitive binding assay and severely defective in basal and stimulated cAMP production and ERK1/2 phosphorylation. Nine mutants had decreased basal cAMP signaling. Seven mutants were constitutively active in cAMP signaling and their basal activities could be inhibited by two MC4R inverse agonists, Ipsen 5i and ML00253764. Five mutants were also constitutively active in the MAPK pathway with enhanced basal ERK1/2 phosphorylation. In summary, our study provided comprehensive data on the structure–function relationship of the TM6 of MC4R. We identified residues that are important for cell surface expression, ligand binding, cAMP generation, and residues for maintaining the WT receptor in active conformation. We also reported constitutive activation of the MAPK pathway and biased signaling. These data will be useful for rationally designing MC4R agonists and antagonists for treatment of eating disorders.

scholarly journals A Feed-Forward Subnetwork Emerging from Integrated TOR- and cAMP/PKA-Signaling Architecture Reinforces Magnaporthe oryzae Appressorium Morphogenesis

2019 ◽  
Vol 32 (5) ◽  
pp. 593-607 ◽  
Author(s):  
Guangchao Sun ◽  
Xiaobo Qi ◽  
Richard A. Wilson
Keyword(s):  
Cell Cycle ◽  
Adenylate Cyclase ◽  
Magnaporthe Oryzae ◽  
Environmental Conditions ◽  
Germ Tube ◽  
Nutrient Status ◽  
Specific Cell ◽  
Appressorium Formation ◽  
G2 Arrest ◽  
Feed Forward

Appressoria are important mediators of plant–microbe interactions. In the devastating rice blast pathogen Magnaporthe oryzae, appressorial morphogenesis from germ tube tips requires activated cAMP/PKA signaling and inactivated TOR signaling (TORoff). TORoff temporarily arrests G2 at a metabolic checkpoint during the single round of mitosis that occurs following germination. G2 arrest induces autophagy and appressorium formation concomitantly, allowing reprogression of the cell cycle to G1/G0 quiescence and a single appressorial nucleus. Inappropriate TOR activation abrogates G2 arrest and inhibits cAMP/PKA signaling downstream of cPKA. This results in multiple rounds of germ tube mitosis and the loss of autophagy and appressoria formation. How cAMP/PKA signaling connects to cell cycle progression and autophagy is not known. To address this, we interrogated TOR and cAMP/PKA pathways using signaling mutants, different surface properties, and specific cell cycle inhibitors and discovered a feed-forward subnetwork arising from TOR- and cAMP/PKA-signaling integration. This adenylate cyclase-cAMP-TOR-adenylate cyclase subnetwork reinforces cAMP/PKA-dependent appressorium formation under favorable environmental conditions. Under unfavorable conditions, the subnetwork collapses, resulting in reversible cell cycle-mediated germ tube growth regardless of external nutrient status. Collectively, this work provides new molecular insights on germ tube morphogenetic decision-making in response to static and dynamic environmental conditions.

Complexity of roles and regulation of the PMK1-MAPK pathway in mycelium development, conidiation and appressorium formation in Magnaporthe oryzae

2013 ◽  
Vol 13 (5-6) ◽  
pp. 133-141 ◽  
Author(s):  
Qingchao Jin ◽  
Chanyuan Li ◽  
Youzhi Li ◽  
Jinjie Shang ◽  
Debao Li ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Mapk Pathway ◽  
Appressorium Formation

scholarly journals USH3A transcripts encode clarin-1, a four-transmembrane-domain protein with a possible role in sensory synapses

2002 ◽  
Vol 10 (6) ◽  
pp. 339-350 ◽  
Author(s):  
Avital Adato ◽  
Sarah Vreugde ◽  
Tarja Joensuu ◽  
Nili Avidan ◽  
Riikka Hamalainen ◽  
...  
Keyword(s):  
Transmembrane Domain ◽  
Domain Protein

scholarly journals Rice Plasma Membrane Proteomics Reveals Magnaporthe oryzae Promotes Susceptibility by Sequential Activation of Host Hormone Signaling Pathways

2016 ◽  
Vol 29 (11) ◽  
pp. 902-913 ◽  
Author(s):  
Jidong Cao ◽  
Chao Yang ◽  
Lingjuan Li ◽  
Lan Jiang ◽  
Yao Wu ◽  
...  
Keyword(s):  
Immune Response ◽  
Plasma Membrane ◽  
Magnaporthe Oryzae ◽  
Transmembrane Domain ◽  
Protein Composition ◽  
Aba Signaling ◽  
Massive Growth ◽  
Genes Expression ◽  
Infected Cells ◽  
Infection Stage

Plant plasma membrane (PM) plays important roles in immune response. Here, we utilized quantitative mass spectrometry to explore rice PM protein composition and dynamic changes during Magnaporthe oryzae infection. We report, thus far, the largest rice PM proteome dataset with 3,906 identified proteins, among which 484 proteins were differentially expressed after M. oryzae infection. One third of the identified proteins are predicted to have at least one transmembrane domain. Half of the identified proteins are predicted to have binding functions and over one third of the proteins have enzyme-related functions. In addition, Gene Ontology analyses revealed that abscisic acid (ABA) and cytokinin (CK) signaling were sequentially activated after M. oryzae infection in rice. We found that the activation of ABA signaling and the suppression of rice immune response occurred at the early infection stage, while the activation of CK signaling, the upregulation of sugar transporter genes expression, and the nutrient efflux of infected rice cells occurred at later infection stage. Thus, we further propose that M. oryzae activates ABA signaling to repress rice immune signaling for initial invasion and redirects nutrient efflux of infected cells for massive growth at the later infection stage.

scholarly journals Bypassing Both Surface Attachment and Surface Recognition Requirements for Appressorium Formation by Overactive Ras Signaling in Magnaporthe oryzae

2014 ◽  
Vol 27 (9) ◽  
pp. 996-1004 ◽  
Author(s):  
Xiaoying Zhou ◽  
Xinhua Zhao ◽  
Chaoyang Xue ◽  
Yafeng Dai ◽  
Jin-Rong Xu
Keyword(s):  
Magnaporthe Oryzae ◽  
Pathogenic Fungi ◽  
Mitogen Activated Protein Kinase ◽  
Ras Signaling ◽  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Surface Attachment ◽  
Surface Recognition ◽  
Aerial Hyphae ◽  
Liquid Suspensions

Magnaporthe oryzae forms a highly specialized infection structure called an appressorium for plant penetration. In M. oryzae and many other plant-pathogenic fungi, surface attachment and surface recognition are two essential requirements for appressorium formation. Development of appressoria in the air has not been reported. In this study, we found that expression of a dominant active MoRAS2G18V allele in M. oryzae resulted in the formation of morphologically abnormal appressoria on nonconducive surfaces, in liquid suspensions, and on aerial hyphae without attachment to hard surfaces. Both the Pmk1 mitogen-activated protein kinase cascade and cAMP signaling pathways that regulate surface recognition and appressorium morphogenesis in M. oryzae were overactivated in the MoRAS2G18V transformant. In mutants deleted of PMK1 or CPKA, expression of MoRAS2G18V had no significant effects on appressorium morphogenesis. Furthermore, expression of dominant MoRAS2 in Colletotrichum graminicola and C. gloeosporioides also caused the formation of appressorium-like structures in aerial hyphae. Overall, our data indicate that MoRas2 functions upstream from both the cAMP-PKA and Pmk1 pathways and overactive Ras signaling leads to improper activation of these two pathways and appressorium formation without surface attachment in appressorium-forming pathogens.

scholarly journals A family of rhomboid-like genes: Drosophila rhomboid-1 and roughoid/rhomboid-3 cooperate to activate EGF receptor signaling

2000 ◽  
Vol 14 (13) ◽  
pp. 1651-1663 ◽  
Author(s):  
Jonathan D. Wasserman ◽  
Sinisa Urban ◽  
Matthew Freeman
Keyword(s):  
Molecular Mechanism ◽  
Growth And Development ◽  
Egf Receptor ◽  
Transmembrane Domain ◽  
Large Family ◽  
Egfr Signaling ◽  
Apparent Lack ◽  
Cell Determination ◽  
Domain Protein ◽  
Rate Limiting

As in mammals, the Drosophila EGF receptor controls many aspects of growth and development. The rate limiting component ofDrosophila Egfr signaling is Rhomboid, a seven transmembrane domain protein, whose expression prefigures Egfr signaling. Little is known about the molecular mechanism of Rhomboid function but genetic evidence suggests that it controls the activation of the ligand Spitz, a TGFα-like factor. Spitz/Egfr signaling regulates cell determination in the eye but here there is no apparent function for Rhomboid, an observation that casts doubt on this prevailing model of Rhomboid function. We describe our identification of six newrhomboid-like genes in Drosophila, and a large family of related genes present in organisms as diverse as bacteria and mammals; a human rhomboid homolog has also recently been described. Drosophila rhomboid-3 corresponds to theroughoid mutation; it cooperates with rhomboid-1 to control Egfr signaling in the eye, thereby solving the puzzle of the apparent lack of Rhomboid-1 function there. Rhomboid-1 and Roughoid/Rhomboid-3 act in the signal-emitting not signal-receiving cell, supporting the idea that Spitz activation is regulated by Rhomboid-like molecules.

scholarly journals Peripheral Coupling Sites Formed by STIM1 Govern the Contractility of Vascular Smooth Muscle Cells

2021 ◽  
Author(s):  
Vivek Krishnan ◽  
Sher Ali ◽  
Albert L. Gonzales ◽  
Pratish Thakore ◽  
Caoimhin S. Griffin ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Transmembrane Domain ◽  
Muscle Cells ◽  
Channel Activity ◽  
Resistance Arteries ◽  
Store Depletion ◽  
Domain Protein

Peripheral coupling between the sarcoplasmic reticulum (SR) and plasma membrane (PM) forms signaling complexes that regulate the membrane potential and contractility of vascular smooth muscle cells (VSMCs), although the mechanisms responsible for these membrane interactions are poorly understood. In many cells, STIM1 (stromal interaction molecule 1), a single transmembrane-domain protein that resides in the endoplasmic reticulum (ER), transiently moves to ER-PM junctions in response to depletion of ER Ca2+ stores and initiates store-operated Ca2+ entry (SOCE). Fully differentiated VSMCs express STIM1 but exhibit only marginal SOCE activity. We hypothesized that STIM1 is constitutively active in contractile VSMCs and maintains peripheral coupling. In support of this concept, we found that the number and size of SR-PM interacting sites were decreased and SR-dependent Ca2+ signaling processes were disrupted in freshly isolated cerebral artery SMCs from tamoxifen-inducible, SMC specific STIM1-knockout (Stim1-smKO) mice. VSMCs from Stim1-smKO mice also exhibited a reduction in nanoscale colocalization between Ca2+-release sites on the SR and Ca2+-activated ion channels on the PM, accompanied by diminished channel activity. Stim1-smKO mice were hypotensive and resistance arteries isolated from them displayed blunted contractility. These data suggest that STIM1 – independent of SR Ca2+ store depletion – is critically important for stable peripheral coupling in contractile VSMCs.

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