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MGP004091

UniProt Annotations

Entry Information

Gene Name	hyperpolarization activated cyclic nucleotide gated potassium channel 4
Protein Entry	HCN4_HUMAN
UniProt ID	Q9Y3Q4
Species	Human

Comments

Comment type	Description
Disease	Brugada syndrome 8 (BRGDA8) [MIM:613123]: A tachyarrhythmia characterized by right bundle branch block and ST segment elevation on an electrocardiogram (ECG). It can cause the ventricles to beat so fast that the blood is prevented from circulating efficiently in the body. When this situation occurs, the individual will faint and may die in a few minutes if the heart is not reset. {ECO:0000269\|PubMed:19165230}. Note=The disease is caused by mutations affecting the gene represented in this entry.
Disease	Sick sinus syndrome 2 (SSS2) [MIM:163800]: The term 'sick sinus syndrome' encompasses a variety of conditions caused by sinus node dysfunction. The most common clinical manifestations are syncope, presyncope, dizziness, and fatigue. Electrocardiogram typically shows sinus bradycardia, sinus arrest, and/or sinoatrial block. Episodes of atrial tachycardias coexisting with sinus bradycardia ('tachycardia-bradycardia syndrome') are also common in this disorder. SSS occurs most often in the elderly associated with underlying heart disease or previous cardiac surgery, but can also occur in the fetus, infant, or child without heart disease or other contributing factors. SSS2 onset is in utero or at birth. {ECO:0000269\|PubMed:16407510, ECO:0000269\|PubMed:20662977}. Note=The disease is caused by mutations affecting the gene represented in this entry.
Domain	The segment S4 is probably the voltage-sensor and is characterized by a series of positively charged amino acids at every third position.
Enzyme Regulation	Activated by cAMP. cAMP binding causes a conformation change that leads to the assembly of an active tetramer and channel opening. {ECO:0000269\|PubMed:16407510, ECO:0000269\|PubMed:20829353, ECO:0000269\|PubMed:22006928}.
Function	Hyperpolarization-activated ion channel with very slow activation and inactivation exhibiting weak selectivity for potassium over sodium ions. Contributes to the native pacemaker currents in heart (If) that regulate the rhythm of heart beat. May contribute to the native pacemaker currents in neurons (Ih). May mediate responses to sour stimuli. {ECO:0000269\|PubMed:10228147, ECO:0000269\|PubMed:10430953, ECO:0000269\|PubMed:16407510, ECO:0000269\|PubMed:19165230, ECO:0000269\|PubMed:20829353}.
Interaction	Self; NbExp=2; IntAct=EBI-1753521, EBI-1753521;
Miscellaneous	Inhibited by extracellular cesium ions.
Similarity	Belongs to the potassium channel HCN family. {ECO:0000305}.
Similarity	Contains 1 cyclic nucleotide-binding domain. {ECO:0000255\|PROSITE-ProRule:PRU00060}.
Subcellular Location	Cell membrane {ECO:0000269\|PubMed:10228147, ECO:0000269\|PubMed:10430953, ECO:0000269\|PubMed:16407510}; Multi- pass membrane protein {ECO:0000269\|PubMed:10228147, ECO:0000269\|PubMed:10430953, ECO:0000269\|PubMed:16407510}.
Subunit	Homotetramer. The potassium channel is composed of a homo- or heterotetrameric complex of pore-forming subunits. {ECO:0000269\|PubMed:20829353, ECO:0000269\|PubMed:22006928}.
Tissue Specificity	Highly expressed in thalamus, testis and in heart, both in ventricle and atrium. Detected at much lower levels in amygdala, substantia nigra, cerebellum and hippocampus. {ECO:0000269\|PubMed:10228147, ECO:0000269\|PubMed:10430953}.