The ciliary beat in the protozoan Paramecium tetraurelia is modulated by cyclic nucleotides and Ca2+. The objective is to understand the role of protein phosphorylation in this regulation. Constitutively active forms of the cAMP dependent, cGMP-dependent, and Ca2+ dependent protein kinases previously purified from Paramecium will be prepared and either microinjected into living cells or applied to permeabilized cells. The effects of these activated enzymes upon swimming speed and direction will be compared with those elicited by cAMP, cGMP, and Ca2+, to establish that protein kinases mediate the effects of the second messengers. To determine whether ion channels are regulated by phosphorylation, voltage-clamp studies of intact cells injected with each kinase will be performed, and the effect of purified protein kinases upon the activity of single channels in excised somatic membrane patches will be studied by patch-clamping. To identify axonemal targets of regulatory phosphorylation, the effect of exogenously added protein kinases on dynein ATPase in permeabilized cells and isolated cilia will be studied. An in vitro assay system for dynein- catalyzed microtubule motility will be used to assess the effect of each protein kinase on dynein's activity. Behavioral mutant defective in membrane excitability or axonemal regulation will be assayed for each of the protein kinases, and the ability of each enzyme to repair the defect in these mutants will be tested by microinjection. The pattern of protein phosphorylation by exogenous protein kinases will be studied in permeabilized cells, isolated cilia, ciliary membranes, axonemes, and purified dyneins. The phosphorylation patterns of wild-type cells will be compared with those of behavioral mutants. These studies should clarify the role of phosphorylation in ion-channel regulation and may lead to the identification of specific membrane proteins as ion channels. The axonemal proteins that mediate regulation by cyclic nucleotides and Ca2+ will be identified, and the differential actions of cAMP and cGMP on ciliary motion may be explained. The regulation of ciliary motion is important to the normal function of ciliated epithelium in such human tissues as trachea, lungs, and oviduct, and to the motility of sperm. Ion-channel regulation is central to neural function.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM034906-09
Application #
2177640
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1990-12-15
Project End
1994-11-30
Budget Start
1993-12-01
Budget End
1994-11-30
Support Year
9
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Wisconsin Madison
Department
Biochemistry
Type
Schools of Earth Sciences/Natur
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Kim, Kwanghee; Son, Min; Peterson, Joan B et al. (2002) Ca(2+)-binding proteins of cilia and infraciliary lattice of Paramecium tetraurelia: their phosphorylation by purified endogenous Ca(2+)-dependent protein kinases. J Cell Sci 115:1973-84
Kim, K; Messinger, L A; Nelson, D L (1998) Ca2+-dependent protein kinases of Paramecium--cloning provides evidence of a multigene family. Eur J Biochem 251:605-12
Mimikakis, J L; Nelson, D L; Preston, R R (1998) Oscillating response to a purine nucleotide disrupted by mutation in Paramecium tetraurelia. Biochem J 330 ( Pt 1):139-47
Mimikakis, J L; Nelson, D L (1998) Evidence for two separate purinergic responses in Paramecium tetraurelia: XTP inhibits only the oscillatory responses to GTP. J Membr Biol 163:19-23
Clark, K D; Hennessey, T M; Nelson, D L et al. (1997) Extracellular GTP causes membrane-potential oscillations through the parallel activation of Mg2+ and Na+ currents in Paramecium tetraurelia. J Membr Biol 157:159-67
Wassenberg, J J; Clark, K D; Nelson, D L (1997) Effect of SERCA pump inhibitors on chemoresponses in Paramecium. J Eukaryot Microbiol 44:574-81
Ann, K S; Nelson, D L (1996) A nucleoside diphosphate kinase from Paramecium tetraurelia with protein kinase activity. J Eukaryot Microbiol 43:365-72
Hochstrasser, M; Carlson, G L; Walczak, C E et al. (1996) Paramecium has two regulatory subunits of cyclic AMP-dependent protein kinase, one unique to cilia. J Eukaryot Microbiol 43:356-62
Carlson, G L; Nelson, D L (1996) The 44-kDa regulatory subunit of the Paramecium cAMP-dependent protein kinase lacks a dimerization domain and may have a unique autophosphorylation site sequence. J Eukaryot Microbiol 43:347-56
Carlson, G L; Nelson, D L (1995) Isolation and characterization of protein kinases from Paramecium cilia. Methods Cell Biol 47:473-80

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