N-Methyl-D-aspartate receptor-mediated chemotaxis and Ca(2+) signaling in Tetrahymena pyriformis.
Although the ciliate Tetrahymena is a good model for the study of chemotaxis, its profound motility makes it difficult to monitor intracellular calcium (Ca(2+)) changes induced by chemotactic stimuli. In this study, we report a microfluidic-based chemotaxis system generating directional chemotactic gradients under highly viscous conditions, suppressing T. pyriformis motility, and allowing for the stable confocal imaging of changes in intracellular Ca(2+) in the ciliate. Once the viscous condition was achieved, directional chemical gradients were formed inside the center chamber via the release of N-methyl-d-aspartate (NMDA), a known chemoattractant, from the surrounding chemical reservoirs into the center chamber. As a result, intracellular Ca(2+) in the ciliate increased up to three-fold, and its distribution was skewed in the direction of NMDA stimulation. However, the Ca(2+) in ciliates pretreated with phospholipase C (PLC) or phosphatidylinositol-3-kinase (PI3K) blockers did not increase even after stimulation. Additionally, the PI3K blocker induced the secretion of granules, the size of which was dependent on the concentration of the blocker. Collectively, the results indicate that both PLC and PI3K perform pivotal roles in controlling the levels of intracellular Ca(2+) in T. pyriformis during chemotaxis.
Nam
Seong-Won
SW
Department of Chemistry and Nano Sciences (BK21), Ewha Womans University, Daehyundong, Seodaemungu, Seoul 120-750, Korea.
Kim
Sang-Tae
ST
Lee
Kang-Mu
KM
Kim
So Hyun
SH
Kou
Songzi
S
Lim
Jeesun
J
Hwang
Hyejin
H
Joo
Min Kyung
MK
Jeong
Byeongmoon
B
Yoo
Seung Hyun
SH
Park
Sungsu
S
D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D002633:Chemotaxis; D016202:N-Methylaspartate / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*; D013769:Tetrahymena pyriformis / Q000235:genetics / Q000502:physiology*
D015800:Protozoan Proteins; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; D002118:Calcium