n-glycosylation mediation of plant immunity in arabidopsis matt borchardt and jessica allen
TRANSCRIPT
N-Glycosylation mediation of Plant Immunity in Arabidopsis
Matt Borchardt and Jessica Allen
Max-Planck Society for the Advancement of Science
• Originally created as the Kaiser Wilhelm Society in 1911, changed in 1948
• Boasts 32 Nobel Prizes awarded to their scientists• Top Non-University Institution in Science by Times
Higher Education• Albert Einstein, Fritz Haber, and Peter Debye were
named directors at some point in its history
http://en.wikipedia.org/wiki/Max-Planck-Gesellschaft
• Arabidopsis– Brassicaceae family– model organism• ABC Plant Model
– First plant to have entire genome sequenced
http://en.wikipedia.org/wiki/Arabidopsis
Signaling in Cells
• Cells are constantly being introduced to various signals inside and outside of the cell– Signal receptors are signal-specific– Causes a cellular response
Example of Cell Signaling
219.221.200.61/ywwy/zbsw(E)/edetail6.htm
Cell Signaling and Plants
• Cell signaling is important for Plant Immunity• Provides feedback systems to promote
cellular defense– Growth inhibition– Production of Reactive Oxygen Species (ROS)• “oxidative burst”
– Apoptosis
Plant Receptors
• Pattern Recognition Receptors (PRRs)– membrane-bound protein of the innate immune
system– recognize microbe-associated molecular patterns
(MAMPs) on pathogens– Contain membrane-bound polysaccharides
• Arabidopsis has approximately 56 known RLPs– EFR recognizes and responds to elf18– FLS2 recognizes and responds to flg22
• MAMPs are recognized by N-glycans on PRRs
• N-Glycans– Attach to asparagine residues of
plasma membrane– Initial contact between plant cells
and pathogens
N-glycosylation
• Occurs in eukaryotes during/after translation• Linking of 14-sugar precursor to the
asparagine in the polypeptide chain
12-52.Molecular Biology of the Cell, 4th Edition
Oligosaccharyltransferase Complex
• Transfers the 14-sugar oligosaccharide from dolichol to the protein
• The central step in N-linked glycosylation• Located in the ER• Post-translational modification
http://www.ier.tokushima-u.ac.jp/bunshi-seiri/physiol/images/PfSTT3.jpg
N-Glycosylation Intermediates
Altered/Prevention of N-Glycosylation
• Creates unfolding of proteins • Only correctly folded proteins are exported
from the ER• Causes a reduction in receptor accumulation– Causes lack of receptor-signal induced pathways– Leads to decreased immune response
In this study
– Mutated genes produce plants with modifications in the N-glycosylation steps• stt3a
• Genes present in ER which encode for oligosaccharyltransferase complex
Tunicamycin
- Antibiotic- Blocks glycoprotein synthesis in first step of
glycosylation- Causes arrest of cell cycle in G1- Produced by bacterium Streptomyces
http://fermentek.co.il/tunicamycin.htm
PRR-EFR
PRR-FLS2Plasma Membrane
Golgi Apparatus
Endoplasmic Reticulum
Seedling GrowthROS
BacteriaMAMP
BacteriaMAMP