Recombinant Human HCN4 protein (GST tag N-Terminus)

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

HCN4 also known as hyperpolarization-activated cyclic nucleotide-gated channel 4 is a protein that functions mechanically as an ion channel. It aids in carrying the hyperpolarization-activated non-selective cation current also called I_f or funny current. HCN4 has a molecular mass of about 136 kDa. The channel is expressed prominently in heart tissues particularly in the sinoatrial node which plays an important role in pacemaker activity to regulate heart rate. HCN4 also appears in some regions of the central nervous system and contributes to neural activity.

Biological function summary

Hyperpolarization-activated ion currents mediated by HCN4 contribute to the pacing of cardiac cells. They allow controlled influx of Na^+ and K^+ ions therefore facilitating rhythmic cardiac activity. Although it does not form part of a larger complex HCN4 interacts with auxiliary subunits and regulator proteins that can modulate its activity. It can be influenced by internal cyclic AMP levels leading to changes in its kinetics and voltage dependency.

Pathways

The involvement of HCN4 mostly figures into cardiac conduction and neuronal signaling pathways. Within the cardiac conduction system it plays a pivotal role in maintaining coordinated heart rhythms. HCN4's function relates to proteins like HCN1 HCN2 and HCN3 which together form a family responsible for various rhythmic activities in the heart and brain. It also assists in stabilizing neuronal firing patterns influenced by neurotransmitter-mediated effects but has less direct interaction with these related proteins.

Mutations or dysfunctions in HCN4 can lead to cardiac arrhythmias like bradycardia. Abnormalities in the function of this protein can also contribute to sick sinus syndrome a condition characterized by problems with the sinoatrial node that affects heart rhythm. In these scenarios HCN4's interaction with other channel proteins and regulatory molecules becomes important as interventions might target these associated pathways for treatment.