Ion channels, such as the K^+ channel, can have open and closed forms that respo

Question

Ion channels, such as the K^+ channel, can have open and closed forms that respond to membrane potential. In addition, an amino - terminal domain, called the inactivation domain or inactivation gate, can block the channel. This is called the ball and chain model of channel inactivation. Identity the statements that correctly describe the ball and chain model. There is more than one true statement. Select all that apply. A shorter nether or chain peptide strand attached to the inactivation domain would increase the time required to inactivate the K^+ channel. After depolarization and channel opening, the inactivation gate soon occludes the open channel The inactivation gate can only inactivate a channel that has closed in response to depolarization. causing the loss of the inactivation gate in K^+ channels could result in membrane that undergoes repolarization more slowly.

Explanation / Answer

The process of depolarization results in opening of channels by transition of the activation gate and then enters a long-living non-conducting and inactivated state. The inactivation gate occludes the ion pore until the membrane is depolarized.

In ball and chain method, the inactivation is achieved by tethering of inactivation particle (ball) to the cytoplasmic face by a protease cleavable domain.

A mutation leads to loss of the inactivation gate in the K+ channels, which results in a membrane that undergoes repolarization more slowly.

Thus, the correct options among the following are 2 and 4.

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