February 9, 2001Science
TRP-PLIK, a Bifunctional Protein with Kinase and Ion Channel Activities
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Discussion
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Implication
In vitro study demonstrates dual kinase and channel activity in TRP-PLIK, indicating that intrinsic enzymatic kinase function is essential for ion conductance.
Key Points
- Clone and characterize the molecular, enzymatic, and electrophysiological properties of the novel bifunctional protein TRP-PLIK.
- Cloned TRP-PLIK and expressed it heterologously in CHO-K1 cell lines to record channel currents.
- Evaluated autophosphorylation and the functional role of the zinc-finger alpha-kinase domain using site-directed mutagenesis and intracellular ATP dependence assays.
- Heterologous expression revealed widely distributed, nonselective, calcium-permeant conductances with 105-picosiemen amplitude and steep outward rectification.
- TRP-PLIK demonstrated functional autophosphorylation mediated by its zinc-finger-containing alpha-kinase domain.
- Inactivation of kinase activity by targeted mutagenesis or ATP limitation completely disrupted channel operation, establishing that intrinsic kinase function is required for channel conductance.
Cite This Study
Runnels et al. (2001) studied this question.