CatSper and Two-Pore channels

Unless otherwise stated all data on this page refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).


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CatSper channels (CatSper1-4, nomenclature as agreed by NC-IUPHAR [10]) are putative 6TM, voltage-gated, calcium permeant channels that are presumed to assemble as a tetramer of α-like subunits and mediate the current ICatSper [15]. In mammals, CatSper subunits are structurally most closely related to individual domains of voltage-activated calcium channels (Cav) [26]. CatSper1 [26], CatSper2 [25] and CatSpers 3 and 4 [14,19,24], in common with a putative 2TM auxiliary CatSperβ protein [18] and two putative 1TM associated CatSperγ and CatSperδ proteins [8,30], are restricted to the testis and localised to the principle piece of sperm tail.

Two-pore channels (TPCs) are structurally related to CatSpers, CaVs and NaVs. TPCs have a 2x6TM structure with twice the number of TMs of CatSpers and half that of CaVs. There are three animal TPCs (TPC1-TPC3). Humans have TPC1 and TPC2, but not TPC3. TPC1 and TPC2 are localized in endosomes and lysosomes [2]. TPC3 is also found on the plasma membrane and forms a voltage-activated, non-inactivating Na+ channel [3]. All the three TPCs are Na+-selective under whole-cell or whole-organelle patch clamp recording [4-5,32]. The channels may also conduct Ca2+ [22].

Channels and Subunits

CatSper1 Show summary » More detailed page

CatSper2 Show summary » More detailed page

CatSper3 Show summary » More detailed page

CatSper4 Show summary » More detailed page

TPC1 Show summary » More detailed page

TPC2 Show summary » More detailed page


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Further reading

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NC-IUPHAR subcommittee and family contributors

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How to cite this family page

Database page citation:

David E. Clapham. CatSper and Two-Pore channels. Accessed on 25/11/2015. IUPHAR/BPS Guide to PHARMACOLOGY,

Concise Guide to PHARMACOLOGY citation:

Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Catterall WA, Spedding M, Peters JA and Harmar AJ, CGTP Collaborators. (2013) The Concise Guide to PHARMACOLOGY 2013/14: Ion Channels. Br J Pharmacol. 170: 1607–1651.