Ion channel (eukaryotic)
Potassium channel Kv1.2 (with beta2 auxiliary subunits), structure in a membrane-like environment. Calculated hydrocarbon boundaries of the lipid bilayer are indicated by red and blue dots.
Identifiers
SymbolIon_trans
PfamPF00520
InterProIPR005821
SCOP21bl8 / SCOPe / SUPFAM
TCDB1.A.1
OPM superfamily8
OPM protein2a79
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
PDB1qg9A:157-176 2a79B:225-409 1ho7A:378-397 1ho2A:378-397 1ujlA:570-611
Ion channel (bacterial)
Potassium channel KcsA. Calculated hydrocarbon boundaries of the lipid bilayer are indicated by red and blue dots.
Identifiers
SymbolIon_trans_2
PfamPF07885
InterProIPR013099
SCOP21bl8 / SCOPe / SUPFAM
OPM protein1r3j
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
PDB1lnqE:25-100 2a0lB:169-250 1orqC:169-250

1k4cC:34-116 1r3iC:34-116 2bocC:34-116 1j95C:34-116 1r3lC:34-116 1jvmB:34-116 1bl8C:34-116 2a9hD:34-116 1k4dC:34-116 1r3jC:34-116 1r3kC:34-116 2bobC:34-116

1p7bB:77-151

The transmembrane cation channel superfamily was defined in InterPro and Pfam as the family of tetrameric ion channels. These include the sodium, potassium,[1] calcium, ryanodine receptor, HCN, CNG, CatSper, and TRP channels. This large group of ion channels apparently includes families 1.A.1, 1.A.2, 1.A.3, and 1.A.4 of the TCDB transporter classification.

They are described as minimally having two transmembrane helices flanking a loop which determines the ion selectivity of the channel pore. Many eukaryotic channels have four additional transmembrane helices (TM) (Pfam PF00520), related to or vestigial of voltage gating. The proteins with only two transmembrane helices (Pfam PF07885) are most commonly found in bacteria. This also includes the 2-TM inward-rectifier potassium channels (Pfam PF01007) found primarily in eukaryotes. There are commonly additional regulatory domains which serve to regulate ion conduction and channel gating. The pores may also be homotetramers or heterotetramers; where heterotetramers may be encoded as distinct genes or as multiple pore domains within a single polypeptide. The HVCN1 and Putative tyrosine-protein phosphatase proteins do not contain an expected ion conduction pore domain, but rather have homology only to the voltage sensor domain of voltage gated ion channels.

Human channels with 6 TM helices

Cation

Transient receptor potential

Main article: Transient receptor potential channel
Canonical

Main article: Canonical TRP channels
Melastatin

Main article: Melastatin TRP channels
Vanilloid

Main article: Vanilloid TRP channels
Mucolipin

Main article: Mucolipin TRP channels
Ankyrin

Main article: Ankyrin TRP channels
TRPP

Main article: Transient Receptor Potential Polycystic

Calcium

Voltage-dependent

Main article: Voltage-dependent calcium channels

Sperm

Main article: Cation channels of sperm

Ryanodine receptor

Main article: Ryanodine receptor

Potassium

Voltage-gated potassium

Main article: Voltage-gated potassium channels
Delayed rectifier
A-type potassium
Outward-rectifying
Inwardly-rectifying
Slowly activating
Modifier/silencer

Calcium-activated

Main article: Calcium-activated potassium channels
BK

Main article: BK channels
SK

Main article: SK channels
IK

Main article: IK channels
Other subfamilies

Inward-rectifier potassium

Main article: Inward-rectifier potassium ion channel

Sodium

Cyclic nucleotide-gated

Proton

Related proteins

Human channels with 2 TM helices in each subunit

Potassium

Tandem pore domain potassium channel

Main article: Tandem pore domain potassium channel

Non-human channels

Two-pore

Main article: Two-pore channels

Pore-only potassium

Main article: Pore-only potassium channels

Ligand-gated potassium

Voltage-gated potassium

Main article: Voltage-gated potassium channels

Prokaryotic KCa

Main article: Prokaryotic KCa channels

Voltage and cyclic nucleotide gated potassium

Sodium

Non-selective

Prokaryotic inward-rectifier potassium

Main article: Inward-rectifier potassium channels

Engineered

References

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External links

This article incorporates text from the public domain Pfam and InterPro: IPR005821
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