With the hopes of one day manipulating cilia's activities on the perimeter of cells and, thus, how those activities affect human health, the team traced cilia's molecular roots into the depths of cells themselves.
If a cilium had a life story, it would begin with a gene. That gene encodes information during a cell's production of tubulin proteins so that they will link up into microtubules, or tiny tubes, and form the interior apparatus of a protruding cilium.
Scientists have known for some time that a group of enzymes can indirectly affect what goes on inside cilia by adding unusually branched chains of amino acids, known as glutamates, onto certain spots of the tubulin proteins that make up the microtubules. Suspecting that the addition of the amino acid chains on the tubulin building blocks might influence how material is transported within cilia, Setou's team took a closer look at how and where the chains of amino acids are added to tubulin proteins and set out to figure out what, ultimately, removed those same chains.
To do so, they analyzed cilia on cells of sensory neurons in a living model organism, the roundworm, and studied purified protein from cultured mouse cells. Ultimately, the enzyme that strips the amino acid chains was elusive no more.
"We found out which enzyme removes part of the glutamate chain, and we now have a better understanding of that lengthening and shortening of amino acids on tubulin that regulates the function of cilia in sensory nerves," he said.
Setou is hopeful the finding will help develop therapies for a group of genetic diseases known as retinitis pigmentosa, which causes degeneration of the eye's retina and, thus, progressive loss of sight.
The human photoreceptor is a sensory neuron
|Contact: Angela Hopp|
American Society for Biochemistry and Molecular Biology