Ion Channels - L3

What must be accounted for in terms of the size of the pore?

What is an ion channel similar to? Why?

How is ion flow facilitated?

What is the Kv1.2 channel?

How was the Kv1.2 channel first discovered?

What channel was discovered by MacKinnon?

As a result of the many (K+) channels with similar amino acid sequences in a variety of organisms, what was it possible to determine?

What are the different techniques for studying ion channels? (8)

What determines the charge of the pore and therefore which ion can pass through?

Describe the carbonyl residue

How does the residue function in the pore? What does this mean in terms of ion selectivity?

How many K+ interact with the Kv selectivity filter? What causes the expulsion of a K+ across the ion channel?

What prevents 'too tight' binding and ensures flow of ions?

What determines the direction of ion flow?

When can a rectifying channel be made to open in the other direction? What does this show?

How does the size of Na+ channels compare to K+ channels? Why don't they pass through Na+ channels?

Give an example of a note very selective ligand gated channel - which ions does it allow to pass through?

What is required to push an NMDA receptor into the open configuration?

What causes the gating currents? (4 steps)

How can antibodies be used to determine the structure of voltage gated channels?

What does each subunit of a voltage-gated channel consist of?

Give 3 examples of tetrameric ion channels?

Give an example of pentamer channel?

Give an example of a hexamer?

Which Kv subunits form the voltage sensitive domain? The pore domain? Are domains hydrophobic or hydrophilic?

What subunits make up a Kv channel?

What is the function of B subunits?

How do Kv(Ca) channel differ?

How do B subunits differ from a subunits?

What is the function of the S4 region, how does it vary between animals?

Where is the voltage sensitive region of the VG Na+ channel? Pore binding?

Where does inactivation of the Na+ channels occur?

How do mutations which cause slow inactivation identify parts of channels?

What is the KCNQ1 channel?

What is the KCNK channel? What is it important for?

How many subunits does a KCNK channel consist of?

How else does a KCNK channel differ from the standard Kv channel?

What are the three other important properties of KCNK channels?

How many domains does a Na a subunit have?

What mutation can occur at S5 of the a subunit? What does this result in?

What mutation can occur at the inactivating loop of the a subunit? (2) What does this result in?

What else causes hyperkalemic periodic paralysis?

What else causes Paramyotonia congenita? (2)

What does HYPP cause in horses?

Which of the two Na+ channelopathies is temperature dependent?

What is a K+ channelopathy that can prove fatal? When is this seen in normal physiological conditions?