KCNMB3

MaxiK channels are large conductance, voltage and calcium-sensitive potassium channels which are fundamental to the control of smooth muscle tone and neuronal excitability. MaxiK channels can be formed by 2 subunits: the pore-forming alpha subunit and the modulatory beta subunit. The protein encoded by this gene is an auxiliary beta subunit which may partially inactivate or slightly decrease the activation time of MaxiK alpha subunit currents. Alternative splicing results in multiple transcript variants. A related pseudogene has been identified on chromosome 22. [provided by RefSeq, Jul 2009]

Potassium Calcium-Activated Channel Subfamily M Regulatory Beta Subunit 3

Regulatory subunit of the calcium activated potassium KCNMA1 (maxiK) channel. Modulates the calcium sensitivity and gating kinetics of KCNMA1, thereby contributing to KCNMA1 channel diversity. Alters the functional properties of the current expressed by the KCNMA1 channel. Isoform 2, isoform 3 and isoform 4 partially inactivate the current of KCNBMA. Isoform 4 induces a fast and incomplete inactivation of KCNMA1 channel that is detectable only at large depolarizations. In contrast, isoform 1 does not induce detectable inactivation of KCNMA1. Two or more subunits of KCNMB3 are required to block the KCNMA1 tetramer.

Action potentialManual Assertion Based On ExperimentIDA:UniProtKB
Detection of calcium ionManual Assertion Based On ExperimentIDA:UniProtKB
Neuronal action potentialManual Assertion Based On ExperimentIDA:UniProtKB
Potassium ion transportManual Assertion Based On ExperimentIDA:UniProtKB

Membrane

Cytoplasmic: 1-60
Helical: 61-81
Extracellular: 82-207
Helical: 208-228
Cytoplasmic: 229-279

N-glycosylated.
The extracellular domain contains disulfide bond essential for the gating mechanism.