title: GTP avoidance in Tetrahymena thermophila requires tyrosine kinase activity, intracellular calcium, NOS, and guanylyl cyclase.
abstract: Guanosine 5'-triphosphate (GTP) is a chemorepellent in Tetrahymena thermophila that has been shown to stimulate cell division as well as ciliary reversal. Previous studies have proposed that GTP avoidance is linked to a receptor-mediated, calcium-based depolarization. However, the intracellular mechanisms involved in GTP avoidance have not been previously documented. In this study, we examine the hypothesis that GTP signals through a tyrosine kinase pathway in T. thermophila. Using behavioral assays, enzyme immunosorbent assays, Western blotting, and immunofluorescence, we present data that implicate a tyrosine kinase, phospholipase C, intracellular calcium, nitric oxide synthase (NOS) and guanylyl cyclase in GTP signaling. The tyrosine kinase inhibitor genistein eliminates GTP avoidance in Tetrahymena in behavioral assays. Similarly, pharmacological inhibitors of phospholipase C, NOS, and guanylyl cyclase all eliminated Tetrahymena avoidance to GTP. Immunofluorescence data shows evidence of tyrosine kinase activity in the cilia, suggesting that this enzyme activity could be directly involved in ciliary reversal.
authors: Department of Science and Mathematics, Cedarville University, Cedarville, OH, 45314, USA.
authors: Janine
authors: J
authors: Bartholomew
authors: Johnathan
authors: J
authors: Reichart
authors: Romie
authors: R
authors: Mundy
authors: Jacquelyn
authors: J
authors: Recktenwald
authors: Shannon
authors: S
authors: Keyser
authors: Mark
authors: M
authors: Riddle
authors: Heather
authors: H
authors: Kuruvilla