ISSN:
1432-1424
Keywords:
calmodulin
;
Ca2+-dependent K+ channels
;
ion channel regulation
;
mutations
;
Paramecium
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary Paramecium tetraurelia possesses two Ca2+-dependent K+ currents, activated upon depolarizationI K(Ca,d), or upon hyperpolarizationI K(Ca,h). The two currents are mediated by pharmacologically distinct ion channel populations. Three mutations ofP. tetraurelia affect these current.s Pantophobiac A mutations (pntA) cause calmodulin sequence defects, resulting in the loss of both Ca2+-dependent K+ currents. A second mutation, TEA-insensitive A (teaA), greatly enhancesI K(Ca,d) but has no affect onI K(Ca,h). A third mutation,restless (rst), also increasesI K(Ca,d) slightly, but its principle effect is in causing an early activation ofI K(Ca,h). Interactions between the products of these three genes were investigated by constructing three double mutants. BothteaA andrst restoreI K(Ca,d) andI K(Ca,h) in pantophobiac A1, but the phenotypes ofteaA andrst are not corrected by a second mutation. These observations may indicate a role for the gene products ofteaA andrst in regulating the activity ofI K(Ca,d) andI K(Ca,h), respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01869106
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