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CatSper and Two-Pore channels C

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, alkalinization-activated 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 [8,31], are restricted to the testis and localised to the principle piece of sperm tail. The novel cross-species CatSper channel inhibitor, RU1968, has been proposed as a useful tool to aid characterisation of native CatSper channels [27].

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 [4-5,33]. The channels may also conduct Ca2+ [22].

Channels and Subunits

Targets of relevance to immunopharmacology are highlighted in blue

CatSper1 C Show summary » More detailed page

CatSper2 C Show summary » More detailed page

CatSper3 C Show summary » More detailed page

CatSper4 C Show summary » More detailed page

TPC1 C Show summary » More detailed page

TPC2 C 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 (select format):

Concise Guide to PHARMACOLOGY citation:

Alexander SPH, Mathie A, Peters JA, Veale EL, Striessnig J, Kelly E, Armstrong JF, Faccenda E, Harding SD, Pawson AJ, Sharman JL, Southan C, Davies JA; CGTP Collaborators. (2019) The Concise Guide to PHARMACOLOGY 2019/20: Ion channels. Br J Pharmacol. 176 Issue S1: S142-228.