New Modes of GPCR Signalling

ABSTRACT
Structural Feature and Function of hβ-subunits of BK Channel
Jiuping Ding
Key Laboratory of Molecular Biophysics Ministry of Education, College of Life
Science and Technology, Huazhong University of Science and Technology, Wuhan,
Hubei, 430074, China
The functional diversity of large conductance Ca 2+ - and voltage-dependent K + (BK)
channels arises mainly from co-assembly of the pore-forming mSlo α subunits with four
tissue enriched auxiliary β subunits. The structural basis of the interaction between α
subunits with β subunits is not well understood.
Using immunofluorescence and patch clamp techniques, we demonstrated that 1)
four-turn α-helical segment prevents surface expression of the auxiliary hβ2 subunit of
BK-type channel; 2) lysine-rich extracellular rings formed by hβ2 subunits confer the
outward rectification of BK channels; 3) structural basis for toxin resistance of
β4-associated calcium-activated potassium (BK) channels. Those findings provide a
better understanding of the structure and the diverse interactions between α and β
subunits and will improve the design of channel inhibitors.