Molecular Components of Large Conductance Calcium-Activated Potassium (BK) Channels in Mouse Pituitary Corticotropes
Large-conductance calcium- and voltage- activated potassium (BK) channels play a fundamental role in the signaling pathways regulating mouse anterior pituitary corticotrope function. Here we describe the cloning and functional characterization of the components of mouse corticotrope BK channels. RT-...
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Published in | Molecular endocrinology (Baltimore, Md.) Vol. 13; no. 10; pp. 1728 - 1737 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Endocrine Society
01.10.1999
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Online Access | Get full text |
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Summary: | Large-conductance calcium- and voltage- activated
potassium (BK) channels play a fundamental role in the signaling
pathways regulating mouse anterior pituitary corticotrope function.
Here we describe the cloning and functional characterization of the
components of mouse corticotrope BK channels. RT-PCR cloning and splice
variant analysis of mouse AtT20 D16:16 corticotropes revealed robust
expression of mslo transcripts encoding pore-formingα
-subunits containing the mouse homolog of the 59-amino acid STREX-1
exon at splice site 2. RT-PCR and functional analysis, using the
triterpenoid glycoside, DHS-1, revealed that native corticotrope BK
channels are not functionally coupled to β-subunits in
vivo. Functional expression of the STREX-1 containing α-subunit
in HEK 293 cells resulted in BK channels with calcium sensitivity,
single-channel conductance, and inhibition by protein kinase A
identical to that of native mouse corticotrope BK channels. This report
represents the first corticotrope ion channel to be characterized at
the molecular level and demonstrates that mouse corticotrope BK
channels are composed of α-subunits expressing the mouse STREX-1
exon. |
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ISSN: | 0888-8809 1944-9917 |
DOI: | 10.1210/mend.13.10.0355 |