Biotrophic pathogens are believed to strategically manipulate sugar transport in host cells to enhance their access to carbohydrates. However, mechanisms of sugar translocation from host cells to biotrophic fungi such as powdery mildew across the plant–haustorium interface remain poorly understood. To investigate this question, systematic subcellular localisation analysis was performed for all the 14 members of the monosaccharide sugar transporter protein (STP) family in Our results showed that AtSTP8 was mainly localised to the endoplasmic reticulum (ER) and appeared to be recruited to the host‐derived extrahaustorial membrane (EHM) induced by powdery mildew. Functional complementation assays in Our data suggested that the ER‐localised sugar transporter AtSTP8 may be recruited to the EHM where it may be involved in sugar acquisition by haustoria of powdery mildew from host cells in Arabidopsis.
This content will become publicly available on December 1, 2024
- Award ID(s):
- 1942722
- NSF-PAR ID:
- 10477268
- Publisher / Repository:
- Journal of Biological Chemistry
- Date Published:
- Journal Name:
- Journal of Biological Chemistry
- Volume:
- 299
- Issue:
- 12
- ISSN:
- 0021-9258
- Page Range / eLocation ID:
- 105389
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Summary Arabidopsis thaliana . The best candidate AtSTP8 was further characterised for its transport properties inSaccharomyces cerevisiae and potential role in powdery mildew infection by gene ablation and overexpression in Arabidopsis.S. cerevisiae suggested that AtSTP8 can transport a broad spectrum of hexose substrates. Moreover, transgenic Arabidopsis plants overexpressingAtSTP8 showed increased hexose concentration in leaf tissues and enhanced susceptibility to powdery mildew. -
Fidelity of protein targeting is essential for the proper biogenesis and functioning of organelles. Unlike replication, transcription and translation processes, in which multiple mechanisms to recognize and reject noncognate substrates are established in energetic and molecular detail, the mechanisms by which cells achieve a high fidelity in protein localization remain incompletely understood. Signal recognition particle (SRP), a conserved pathway to mediate the localization of membrane and secretory proteins to the appropriate cellular membrane, provides a paradigm to understand the molecular basis of protein localization in the cell. In this chapter, we review recent progress in deciphering the molecular mechanisms and substrate selection of the mammalian SRP pathway, with an emphasis on the key role of the cotranslational chaperone NAC in preventing protein mistargeting to the ER and in ensuring the organelle specificity of protein localization.more » « less
-
more » « less
Abstract Glycosylinositolphosphorylceramides (GIPCs) are the predominant lipid in the outer leaflet of the plasma membrane. Characterized GIPC glycosylation mutants have severe or lethal plant phenotypes. However, the function of the glycosylation is unclear. Previously, we characterized
Arabidopsis thaliana GONST1 and showed that it was a nucleotide sugar transporter which provides GDP‐mannose for GIPC glycosylation.gonst1 has a severe growth phenotype, as well as a constitutive defense response. Here, we characterize a mutant in GONST1’s closest homolog, GONST2. Thegonst2‐ 1 allele has a minor change to GIPC headgroup glycosylation. Like other reported GIPC glycosylation mutants,gonst1‐1gonst2‐1 has reduced cellulose, a cell wall polymer that is synthesized at the plasma membrane. Thegonst2‐1 allele has increased resistance to a biotrophic pathogenGolovinomyces orontii but not the necrotrophic pathogenBotrytis cinerea . Expression of GONST2 under the GONST1 promoter can rescue the gonst1 phenotype, indicating that GONST2 has a similar function to GONST1 in providing GDP‐D‐Man for GIPC mannosylation. -
more » « less
Abstract Integrated computational modeling provides a mechanistic and quantitative framework to characterize alterations in mitochondrial respiration and bioenergetics in response to different metabolic substrates in-silico. These alterations play critical roles in the pathogenesis of diseases affecting metabolically active organs such as heart and kidney. Therefore, the present study aimed to develop and validate thermodynamically constrained integrated computational models of mitochondrial respiration and bioenergetics in the heart and kidney cortex and outer medulla (OM). The models incorporated the kinetics of major biochemical reactions and transport processes as well as regulatory mechanisms in the mitochondria of these tissues. Intrinsic model parameters such as Michaelis–Menten constants were fixed at previously estimated values, while extrinsic model parameters such as maximal reaction and transport velocities were estimated separately for each tissue. This was achieved by fitting the model solutions to our recently published respirometry data measured in isolated rat heart and kidney cortex and OM mitochondria utilizing various NADH- and FADH2-linked metabolic substrates. The models were validated by predicting additional respirometry and bioenergetics data, which were not used for estimating the extrinsic model parameters. The models were able to predict tissue-specific and substrate-dependent mitochondrial emergent metabolic system properties such as redox states, enzyme and transporter fluxes, metabolite concentrations, membrane potential, and respiratory control index under diverse physiological and pathological conditions. The models were also able to quantitatively characterize differential regulations of NADH- and FADH2-linked metabolic pathways, which contribute differently toward regulations of oxidative phosphorylation and ATP synthesis in the heart and kidney cortex and OM mitochondria.
-
more » « less
In animals, endocytosis of a seven-transmembrane GPCR is mediated by arrestins to propagate or arrest cytoplasmic G protein–mediated signaling, depending on the bias of the receptor or ligand, which determines how much one transduction pathway is used compared to another. In
Arabidopsis thaliana , GPCRs are not required for G protein–coupled signaling because the heterotrimeric G protein complex spontaneously exchanges nucleotide. Instead, the seven-transmembrane protein AtRGS1 modulates G protein signaling through ligand-dependent endocytosis, which initiates derepression of signaling without the involvement of canonical arrestins. Here, we found that endocytosis of AtRGS1 initiated from two separate pools of plasma membrane: sterol-dependent domains and a clathrin-accessible neighborhood, each with a select set of discriminators, activators, and candidate arrestin-like adaptors. Ligand identity (either the pathogen-associated molecular pattern flg22 or the sugar glucose) determined the origin of AtRGS1 endocytosis. Different trafficking origins and trajectories led to different cellular outcomes. Thus, in this system, compartmentation with its associated signalosome architecture drives biased signaling.
