Developing a 3D animation for deeper molecular understanding of Michaelis-Menten enzyme kinetics

The mathematical models that describe enzyme kinetics are invaluable predictive tools in numerous scientific fields. However, the daunting mathematical language used to describe kinetic behaviour can be confusing for life science students; they often struggle to conceptualize and relate the mathematical representations to the molecular phenomena occurring at both macroscopic and microscopic levels. Students with less developed abstract and mathematical thinking skills may benefit from a visual learning approach. The paucity of visual resources for enzyme kinetics makes this a fertile field for developing novel learning media. We discuss developing a 3D animation aimed at introducing key concepts of Michaelis-Menten enzyme kinetics to undergraduate life science students. This animation uses both realistic and metaphoric depictions of the underlying molecular players, environments, and interactions in enzyme kinetics to contextualize and explain the relationship between the mathematic models and underlying molecular system. In addition, we will present our production pipeline and workflow for creating educational animations as well as didactic strategies that maximize clarity and accessibility in animated media

Molecular mechanisms underlying G protein disturbances in bipolar affective disorder, the role of ADP-ribosylation processes

grantor: University of TorontoThis study examined whether the stimulatory G protein à subunit, Ãs, undergoes ADP-ribosylation in postmortem human brain, and whether disturbances in this pathway contribute to the elevated à s levels reported in bipolar affective disorder (BD). Endogenous, and cholera toxin (CTX)-catalyzed [32P]ADP-ribosylated à s were characterized in postmortem temporal cortex by immunoprecipitation, and overlay comparisons of autoradiograms and Western blots of the [ 32P]ADP-ribosylated Ãs isoforms. Endogenous and CTX-catalyzed [32P]ADP-ribosylated Ãs in temporal, occipital and cerebellar cortices of BD, and age/postmortem delay-matched controls were then separated by SDS-PAGE and autoradiograms quantified by densitometry. à s protein levels were determined by Western blotting. Two major endogenous [32P]ADP-ribosylated products (48 kDa and 45 kDa) were identified as Ãs-L and à s-S, respectively. Immunoprecipitation with Ãs specific antibody revealed a third endogenous [32P]ADP-ribosylated protein (39 kDa). Resolution by SDS-PAGE and limited protease digestion supported that this product corresponded to an Ãs-like protein, possibly a previously reported N-terminal truncated Ãs splice variant. Two major CTX-catalyzed [32P]ADP-ribosylated products were also identified as Ãs-L (52 kDa) and Ãs-S (45 kDa). No differences were observed in either endogenous, and CTX-catalyzed [32P]ADP-ribosylation of Ãs-L in BD temporal cortex. However, Ãs-L immunolabeling was significantly elevated and correlated inversely with endogenously [32P]ADP-ribosylated à s-L in this brain region suggesting reduced clearance of à s-L through the ADP-ribosylation pathway in BD temporal cortex. Reduced CTX-catalyzed [32P]ADP-ribosylation of Ãs-S in BD temporal cortex also supports this interpretation. Moreover, lack of differences in endogenous [32P]ADP-ribosylation of myelin basic protein (MBP) in temporal cortex of BD compared with controls suggests that elevations of Ãs are not due to underlying disturbances in ADP-ribosyltransferase activity but rather may reflect changes in disposition or availability that are specific to Ãs. Endogenous [32P]ADP-ribosylation of the 39 kDa à s-like protein was reduced only in BD temporal cortex. This decrement correlated with lithium concentrations suggesting that lithium may modify the activity of specific ADP-ribosyltransferases in this region. While the results of this study demonstrate that Ãs is a substrate for ADP-ribosylation and that a 39 kDa Ãs-like protein is also expressed in human brain, the findings do not support the hypothesis that alterations in ADP-ribosyltransferase activity per se are responsible for the higher Ãs levels seen in BD cerebral cortex regions.Ph.D