Kir2.1 Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Kir2.1 (encoded by KCNJ2) is an inward rectifier potassium channel critical for maintaining neuronal and cardiac resting membrane potential. These channels conduct potassium ions preferentially in the inward direction at negative potentials, making them essential regulators of cellular excitability.
Kir2.1 has the characteristic structure of inward rectifier potassium channels:
- Primary Structure: Two transmembrane domains (M1 and M2) with intracellular N- and C-termini
- Tetrameric Assembly: Four subunits form functional channels
- Key Regions:
- Pore loop (H5): Between M1 and M2, contains K+ selectivity filter
- G-loop: Intracellular gate controlling ion flow
- Phosphorylation sites: Regulate channel activity
- Interactions: Interacts with PIP2 and intracellular proteins
Kir2.1 mediates strong inward rectifier potassium currents (I_K1):
- Resting Membrane Potential: Major determinant of resting potential (-70 to -90 mV)
- Action Potential Repolarization: Helps terminate the action potential
- Input Resistance: Sets neuronal input resistance
- Dendritic Integration: Modulates synaptic integration in dendrites
¶ Andersen-Tawil Syndrome
- Loss-of-function mutations cause ATS type 1
- Reduced Kir2.1 current leads to:
- Periodic paralysis (hypokalemic)
- Cardiac arrhythmias (Long QT, ventricular tachycardias)
- Developmental abnormalities
- Short QT syndrome (gain-of-function)
- Atrial fibrillation
- Exercise-induced ventricular tachycardia
- Altered Kir2.1 function affects neuronal K+ homeostasis
- Contributes to membrane potential dysregulation
- Potential therapeutic target
- Kir2.1 regulates dopaminergic neuron excitability
- Altered expression in substantia nigra
- Target for neuroprotection
| Drug/Agent |
Mechanism |
Status |
| BaCl2 |
Pore blocker |
Research use only |
| CsCl |
Pore blocker |
Research use only |
| None approved |
Specific activators |
In development |
| None approved |
Specific blockers |
In development |
- Hibino H, et al. (2010). Inwardly rectifying potassium channels. Physiol Rev.
- Lopatin AN, et al. (2001). Molecular basis of inward rectification. Annu Rev Physiol.
- Baukrowitz T, et al. (2002). PIP2 as a signalling molecule. Science.
The study of Kir2.1 Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.