Alternative splicing switches potassium channel sensitivity to protein phosphorylation

Area of Science:

• Molecular biology
• Neuroscience
• Ion channel physiology

Background:

• Large conductance calcium-activated potassium (BK) channels regulate cellular excitability through alternative splicing and phosphorylation.
• BK channels exhibit diverse regulation by cAMP-dependent protein kinase (PKA) in native tissues.
• Differential PKA regulation of alternatively spliced BK channels may explain their varied sensitivities.

Purpose of the Study:

• To investigate how alternative splicing influences BK channel regulation by PKA.
• To determine the molecular mechanisms by which PKA modulates BK channel activity based on splice variants.

Main Methods:

• Electrophysiological recordings of BK channel activity.
• Molecular biology techniques to study alternative splicing and phosphorylation sites.
• Site-directed mutagenesis to identify key regulatory residues.

Main Results:

• PKA activates BK channels lacking splice inserts (ZERO variants).
• PKA inhibits BK channels with the STREX-1 exon insert.
• Activation depends on a C-terminal PKA site (S869), while inhibition involves a STREX-1 specific site.

Conclusions:

• Alternative splicing acts as a molecular switch controlling BK channel response to PKA.
• This mechanism provides a basis for the diversity and plasticity of BK channel regulation.
• Understanding this interplay is crucial for comprehending cellular excitability control.