Simple sugars such as sucrose (found in the sugar bowl) and fructose (in fruits and honey) provide the sweet finishing touches on many holiday treats. But did you know that versions of these molecules also serve important functions in our cells?
Cells assemble sugar molecules into chains known as glycans. These glycans, which can be linear or branching, play an astounding number of biological roles. When bound to proteins called lectins, they enable a fertilized egg to attach properly onto a woman’s uterine wall and help immune cells move out of a blood vessel to the site of an infection. When decorated with specific patterns of molecules called sulfates, glycans can help direct the growth of nerves. And it’s the glycans found on our blood cells that define blood type (A, B, AB or O).
Studying how these important sugar chains work in our bodies has been challenging. Unlike proteins, which are made from a DNA recipe, glycans are not based on genetic instructions. Instead, enzymes work together to build glycans following steps that are hard for scientists to understand. However, thanks to new methods being pioneered by scientists such as Carolyn Bertozzi, who uses chemistry to develop tools to study biological problems , researchers are now able to mark and follow changes in glycans as they function in living cells.
“These new tools have tremendous potential to illuminate the complex roles sugars play in a wide range of basic biological processes,” notes Pamela Marino, who oversees NIGMS-funded research grants in glycobiology. “With the tools becoming available now, we can begin to decipher the chemical language encoded into these glycans. These are indeed very exciting times.”
Check out our coverage of glycobiology to learn more about how sugar is a key ingredient both in and on our cells.