Gary Mo

Illuminating biochemistry both in cells and organisms

Our cells perform biochemical manufacturing and accounting every moment of our lives. To address mishaps in these processes, which invariably lead to diseases, pharmaceuticals must be understood in terms of the strength, specificity, and kinetics with which they interact with cellular biochemistry. Designer proteins, called biosensors, allow us to specifically look into that biochemistry inside live cells, and even living animals. It is the long-term goal of my lab to enrich the ways we can monitor living biochemistry through molecular designs.

Live cell super-resolution activity imaging

Zoom in on living cells. Optical super-resolution allows us to see protein locations, but not activity. It is akin to having the shared GPS locations of friends, but not what they are up to. Living systems use signaling activity as a currency, inside nanodomains of 200 nm or smaller. To resolve activity at this level, we first developed the super-resolution techniques pcSOFI and refSOFI, then coupled it to a discovery we named Fluorescence fLuctuation Increase by Contact (FLINC). The physics of FLINC makes it a highly useful biosensor platform. Like the powerful biosensing technique FRET, FLINC is generalizable to many systems. Thus, we enabled a whole new class of biosensor that utilized fluorescent fluctuations to encode biochemical activity dynamics in living cells at a resolution of 100-160 nm every 30 seconds. The active architectures of many pathways can now be examined at super-resolution.

Multiplexing a complex context

Take a picture. We often forget that there are many interesting things happening in the background, just as much as that in the focus of the shot. In live cells, such background context could mean the difference between activating one branch of biochemistry (a pathway) or another. Even though the visible, blue-to-red spectral real-estate is very limited, we found a way to stack many biosensors together, allowing us to see 3 and perhaps more cast of characters. In this way, we could more holistically and accurately dissect the pathway being activated or shunted in diseases or stem cell differentiation.

Mo GC, Ross B, Hertel F, Manna P, Yang X, Greenwald E, Booth C, Plummer AM, Tenner B, Chen Z, Wang Y, Kennedy EJ, Cole PA, Fleming KG, Palmer A, Jimenez R, Xiao J, Dedecker P, Zhang J. Genetically encoded biosensors for visualizing live-cell biochemical activity at super-resolution. Nat Methods, 2017. PMCID: PMC5388356

Hertel F1, Mo GC, Duwé S, Dedecker P, Zhang J. RefSOFI for Mapping Nanoscale Organization of Protein-Protein Interactions in Living Cells. Cell Rep, 2016. PMCID: PMC4870019

Dedecker P, Mo GC, Dertinger T, Zhang J. Widely accessible method for superresolution fluorescence imaging of living systems. Proc Natl Acad Sci U S A, 2012. PMCID: PMC3390831

Ding Y, Li J, Enterina JR, Shen Y, Zhang I, Tewson PH, Mo GC, Zhang J, Quinn AM, Hughes TE, Maysinger D, Alford SC, Zhang Y, Campbell RE. Ratiometric biosensors based on dimerization-dependent fluorescent protein exchange. Nat Methods, 2015. PMCID: PMC4344385

Wang Y, Ho TG, Bertinetti D, Neddermann M, Franz E, Mo GC, Schendowich LP, Sukhu A, Spelts RC, Zhang J, Herberg FW, Kennedy EJ. Isoform-selective disruption of AKAP-localized PKA using hydrocarbon stapled peptides. ACS Chem Biol, 2014. PMCID: PMC3985448

Mo GC, Yip CM. Supported Lipid Bilayer Templated J-Aggregate Growth: Role of Stabilizing Cation-π Interactions and Headgroup Packing. Langmuir, 2009. PMID: 19645500

Mo GC, Yip CM. Structural templating of J-aggregates: Visualizing bis(monoacylglycero)phosphate domains in live cells. Biochim Biophys Acta Proteins Proteom, 2017. PMID: 28844737