UGGT1 and UGGT2 are key quality control factors that determine the fate of glycoproteins in the early mammalian secretory pathway. These two paralogues direct persistent molecular chaperone binding in the endoplasmic reticulum that helps with protein maturation and sorting. Persistent chaperone binding of terminally misfolded clients can target proteins for degradation by the proteasome, as well as lysosomal proteases. In our study, a quantitative glycoproteomics strategy was developed to identify cellular clients of UGGT1 and UGGT2. Interestingly, UGGT1 was found to preferentially recognize large membrane glycoproteins, while UGGT2 favored the modification of smaller soluble lysosomal proteins. This study opens the door to a detailed understanding of the recognition process for these important quality control factors and identifies targets whose folding trajectories may be altered in disease states. This work, recently published in eLife, blends chemical and cell biological approaches and was a collaborative effort by three CBI students in the lab, spearheaded by lead author Ben Adams. Ben recently started a postdoctoral position at Harvard Medical School. – Dan Hebert
“Our work identified native substrates of an essential protein quality control process and explored it’s role in glycoproteostasis.” – Ben Adams
“Novel substrates of the glucosyltransferases UGGT1 and UGGT2 have been identified and compared to an in silico N-glycoproteome” – Nathan Canniff
“Through a quantitative mass spectrometry approach we have determined endogenous substrates for UDP-glucose:glycoprotein glucosyltransferases (UGGT) 1 & 2, showing both are functional and preferentially target different substrates requiring folding assistance from calnexin and calreticulin” – Kevin Guay
Quantitative glycoproteomics reveals cellular substrate selectivity of the ER protein quality control sensors UGGT1 and UGGT2.Adams BM, Canniff NP, Guay KP, Larsen ISB, Hebert DN. Elife. 2020 Dec 15;9:e63997. doi: 10.7554/eLife.63997.PMID: 33320095. Free PMC article
Press release by Al Crosby, Professor of PSE
A type of damage in soft materials and tissue called cavitation is one of the least-studied phenomena in physics, materials science and biology, say expert observers. But strong evidence suggesting that cavitation occurs in the brain during sudden impact leading to traumatic brain injury (TBI) has accelerated interest recently, say materials scientist Alfred Crosby at the University of Massachusetts Amherst and his team.
Crosby is the senior author of a new “Perspectives” paper in Proceedings of the National Academy of Sciences. The researchers intend it to spark fresh discussion and drive collaboration among new communities of biologists, chemists, materials scientists, physicists and others to advance knowledge. They define high-priority goals and point out new opportunities in the field of how matter deforms and flows with cavitation.
Crosby says, “We’re breaking down barriers that separate different scientific fields to spur progress in understanding cavitation—how it causes difficult-to-diagnose injuries or unseen failure in soft materials.”
He and Ph.D. students Christopher Barney and Carey Dougan, co-first authors of the paper, worked with chemical engineer Shelly Peyton, mechanical engineer Jae-Hwang Lee and polymer scientist Greg Tew at UMass Amherst. Others on the “CAVITATE” team are chemical engineer Rob Riggleman at the University of Pennsylvania and mechanical engineer Shengqiang Cai at the University of California, San Diego. Support is from a $2.6 million grant from the U.S. Office of Naval Research.
“While the world of cavitation seems to be historically the realm of engineers and physicists, there are growing opportunities for synthetic chemistry to contribute to the field,” the authors state. “The chemistry community will significantly aid both the mechanics and biology communities in understanding the physical principles of cavitation as well as using them to advantage in chemical reactions.”
Studied mainly in fluids for many years, cavitation is the creation and collapse of bubbles in liquids, Crosby explains. When bubbles collapse they force liquid into a smaller area, causing a pressure wave and increased temperature, which lead to damage. In a pump, cavitation can erode metal parts over time, for example. Cavitation inside artificial heart valves can damage not only the parts but the blood, he says. Microcavitation in the brain as a result of high-impact blows or being near an explosion are factors in TBI.
Crosby says the team’s perspective paper explores how cavitation can be used not only for preventing damage but also how to use cavitation as a unique tool for understanding soft tissues. For example, new methods use cavitation to study how properties like strength evolve in tissues. Co-first author Barney says the researchers hope to spur new research and development in medicine, chemistry, biology, mechanics and to new uses.
Crosby invented a new experimental tool called cavitation rheology for measuring the local mechanical properties of soft matter. He says, “We hope this will lead to advances in medical devices for diagnosing disease, novel devices for protective gear and new sustainable approaches for cleaning materials.”
Co-first author Dougan adds, “While cavitation is often thought of as something to be avoided, we aim to use it to benefit medicine and the development of new treatments.” For example, cavitation rheology can be used to measure the strength of interfaces within the brain, which is difficult to achieve with any other method, she notes. Specifically for TBI, the authors outline techniques for biologists to establish cavitation rheology as a tool for characterizing mechanical responses of soft biological tissues.
CBI Trainee Weiyue Xin (Santore Lab) took third place in the Annual G.R.A.S.S. (Graduate Research Student Symposium) for her seminar on the interactions between solid domains in biomimetic membranes. Weiyue’s work is part of a larger DOE-sponsored collaboration between the Santore and Grason groups, aiming to understand new mechanisms occurring in membranes made from biomolecules, and how these interactions can be exploited in the creation of new materials.
What a happy coincidence that on the day of the announcement that Jennifer Doudna and Emmanuelle Charpentier were awarded the Nobel Prize in Chemistry for basic science at the interface of Chemistry and Biology, CBI’s monthly Chalk Talk featured the labs of two women, Amanda Woerman and Jeanne Hardy. Jeanne took a moment to mark the historic occasion, expressing both the happiness felt by many who are “really thrilled to be doing science at a time when women are able to do great science and be recognized,” and also encouragement to the entire community to continue to find ways to make science welcoming to everyone.
CBI Trainee Adrian Lorenzana won first prize in the Materials Science and Engineering category in the NOBCChE ConneXions Poster Competition for his poster presentation “Force-responsive Materials Utilizing Cryptic Crosslinking Sites.” Congratulations Adrian!