KvLQT1/KCNE1
KCNE1 (minK), can assemble with KvLQT1 to form a slow delayed potassium rectifier channel. KCNE1 slows the inactivation of KvLQT1 when the two proteins form a heteromeric complex, and the current amplitude is greatly increased compared to WT-KvLQT1 homotetrameric channels. KCNE1 associates with the pore region of KvLQT1, and its transmembrane domain contributes to the selectivity filter of this heteromeric channel complex. The alpha helix of the KCNE1 protein interacts with the pore domain S5/S6 and with the S4 domain of the KvLQT1 channel. This results in structural modifications of the voltage sensor and the selectivity filter of the KvLQT1 channel. Mutations in either the alpha subunit of this complex, KvLQT1 or the beta subunit, KCNE1, can lead to Long QT Syndrome or other cardiac rhythmic deformities. When associated with KCNE1, the KvLQT1 channel activates much more slowly and at a more positive membrane potential. It is believed that two KCNE1 proteins interact with a tetrameric KvLQT1 channel, since experimental data suggests that there are 4 alpha subunits and 2 beta subunits in this complex. KVLQT1/KCNE1 channels are taken up from the plasma membrane through a RAB5 dependent mechanism, but inserted into the membrane by RAB11, a GTPase.
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