Poster abstracts
Poster number 20 submitted by Swapnil Mukherjee
Optogenetic Platform for Dissecting IRE1’s Enzymatic Mechanism
Swapnil Mukherjee (Department of Chemistry and Biochemistry, The Ohio State University), Vladislav Belyy (Department of Chemistry and Biochemistry, Center of RNA Biology, The Ohio State University)
Abstract:
Inositol-requiring enzyme 1 (IRE1) is a bifunctional kinase/RNase that is
regulated by oligomeric transitions. When activated, mammalian IRE1 splices
a specific mRNA encoding the transcription factor X-box binding protein
(XBP1), which in turn helps reduce the load of misfolded proteins in the
endoplasmic reticulum. The precise mechanism by which oligomerization
activates IRE1 is still unknown, in part due to the substantial experimental
challenges associated with studying subtle oligomeric transitions in
low-affinity protein clusters. To overcome this problem, we have engineered
Opto-IRE1, a flexible light-activatable IRE1 platform. Opto-IRE1 allows us to
control the enzyme’s precise stoichiometry at physiologically relevant
concentrations. We have applied Opto-IRE1 to study the functional
consequences of IRE1 dimerization with precise control over each protomer’s
phosphorylation state. Our results build towards a comprehensive picture of
how stoichiometry and phosphorylation collectively control IRE1 activity.
Keywords: Optogenetics, Receptor Oligomerization