Researchers decode protective layer of green alga cilia

Researchers from Germany and Italy have made a significant breakthrough in understanding the ciliary layer of a green alga called Chlamydomonas reinhardtii. Cilia are tiny, hair-like structures on cells that play many roles, such as helping with movement and sensing the environment. The team studied the glycocalyx, a protective sheath around the cilia made of sugar-rich proteins known as glycoproteins. Previously, the structure of this layer was not well understood. They discovered that two main glycoproteins, named FMG1B and FMG1A, are key components of this protective layer. FMG1A is a new variant of FMG1B. These glycoproteins are similar to mucin proteins found in mammals, which are important for forming protective mucus in various parts of the body. The researchers removed these glycoproteins from the alga, finding that the cilia became stickier. Despite this change, the algal cells could still move across surfaces. This suggests that these proteins do not directly help cells stick to surfaces but instead act as a protective layer that controls how sticky the cilia are. According to Prof. Michael Hippler from the University of Münster, this discovery enhances our understanding of how cells interact with their environments. Dr. Adrian Nievergelt from the Max Planck Institute noted that these findings could provide insights into similar protective mechanisms in other organisms. The team employed advanced imaging and protein analysis techniques, including cryogenic electron tomography and electron microscopy, to conduct their study.