Dr. Ligon Presents Research on Cellular Cytoskeletons
by Ben Trachtman '12Science & Technology Editor
November 13, 2009
This past Monday, students filled one of the Science Center's lecture rooms for a presentation by Dr. Lee Ligon about cell shape and structure. Dr. Ligon explained her research on the topic at Rensselaer Polytechnic Institute and its impact on understanding how so many different tissue structures, like nerves and muscles, can form from a few original cells.
Dr. Ligon's talk focused on a cell's cytoskeleton—the system of protein fibers and filaments that gives a cell its shape. Her research has primarily been on one element of the cytoskeleton called microtubules, which are tiny, rigid protein tubes that act like steel girders in holding a cell's membrane in place. In addition to providing support for the cell, microtubules also function as a cell's "super highway system." Other proteins can attach to microtubules and "ride" along them, carrying essential cellular cargo to various points inside the cell.
Previous research has shown that the body naturally modifies some microtubules using certain chemical compounds to change their basic properties. These microtubules are found in different parts of the cell and their different behaviors determine which motor proteins can and cannot attach to them. By having differentiated microtubules go to different places within a cell, materials can be selectively shipped to different locations along these microtubules.
Dr. Ligon, as a Ph.D. in neuroscience, explained how microtubules affect the structure and function of neurons, the basic cell of the nervous system. Neurons have a unique shape that includes an extension of the cell called an axon used to fire electrical impulses. There are axons reaching from your spinal cord to your toes, and microtubules are the essential component that enables one cell to go on for a few feet. Not only do they provide the support necessary for the axon, but they also serve as the road for essential materials to be shipped all the way from the cell body down to the tip of the axon.
Microtubules play another vital role in a different type of cell. There are several places in our body that require cells to have different proteins, channels and receptors on one side of the cell than the other. The digestive system provides a good example – the tissues lining the intestine have to be able to absorb nutrients on one side and deposit them into the bloodstream on the other. Microtubules define the characteristic cylindrical shape of these cells that enables them to fulfill their role. These cells also exhibit differentiated types of microtubules, which allow them to transport the nutrients from the side they were absorbed on to the side they need to leave the cell through.
Even though scientists have known about microtubules since the late 1970s, there is still new research about them. Microtubules are a type of biopolymer, a type of natural molecule composed of smaller components. Biopolymers are becoming an increasingly popular topic of bioengineering research, making our understanding of how they work in a natural system that much more important. They can be used to replace synthetic materials in plastics and packaging, making these products biodegradable and reducing the use of oil for the production of plastics. Further research in the field could revolutionize non-degradable and oil-based plastics, reducing oil dependency and stemming the tide of plastics that is clogging up landfills.
For being so small, microtubules have a huge impact both inside and outside the body. In addition to providing a framework for a cell and a method of transportation for cellular building blocks, they are also crucial in the process of cell division. This means that they are involved in cancer. Chemotherapy inhibits microtubules from extending, preventing cells from dividing and slowing the rapid, uncontrolled cell division characteristic of cancer. There are still many unexplored properties of microtubules that will have an impact on both the medical field and potentially environmentalism as well.