Subtype-Selective Positive Modulation of K_Ca2.3 Channels Increases Cilia Length

Area of Science:

• Molecular Biology
• Cell Biology
• Physiology

Background:

• Small-conductance calcium-activated potassium channels (KCa2.x) are crucial for regulating cellular excitability.
• KCa2.3 channel activation in endothelial cells promotes hyperpolarization, enhancing calcium signaling.
• Cilia function as specialized compartments for calcium signaling within cells.

Purpose of the Study:

• To identify selective modulators of KCa2.3 channels.
• To investigate the role of KCa2.3 channels in endothelial cell calcium signaling and cilia function.
• To explore the implications of KCa2.3 channel modulation in flow-induced responses.

Main Methods:

• Screening for selective KCa2.3 channel potentiators.
• Utilizing electrophysiology and calcium imaging in endothelial cells.
• Employing site-directed mutagenesis to identify key residues for subtype selectivity.

Main Results:

• Compound 4 was identified as a selective potentiator of human KCa2.3 channels over rat KCa2.2a channels.
• Selective potentiation of KCa2.3 channels by compound 4 increased flow-induced calcium signaling and cilia length.
• Pharmacological inhibition (AP14145) or genetic mutation of KCa2.3 channels reduced these effects, confirming channel involvement.

Conclusions:

• KCa2.3 channels and cilia are functionally linked in endothelial cell flow-induced calcium signaling.
• Selective modulation of KCa2.3 channels offers a potential therapeutic strategy for conditions involving endothelial dysfunction.
• Findings suggest implications for vasodilation and ciliopathic hypertension.