Ryanodine-sensitive calcium-release channel impairing toxin (Ryanodine receptor inhibitor)

Channel Ryanodine receptors (RyRs) are ion channels that allow for the release of Ca2+ from the endoplasmic or sarcoplasmic reticulum. They are expressed in many different cell types but are best known for their predominance in skeletal and cardiac myocytes, where they are directly involved in excitation-contraction coupling. RyRs are the largest known ion channel, adopting a homotetrameric structure more than 2000 kDa in mass (Kimlicka and Van Petegem, 2011). Mammals have three RyR isoforms that are widely expressed in a range of both excitable and nonexcitable cells. Despite their prevalence in a variety of tissues, RyR1 is commonly referred to as the skeletal subtype and RyR2 the cardiac subtype. RyR3 was initially discovered in the brain (McPherson and Campbell, 1990) and seems to be the most broadly expressed of the three subtypes (Martin et al., 1998).

Toxin
RyR channels Toxins from different taxa that target RyR channels.
Click on image to retrieve toxins of interest.
Human Snake Scorpion Cone
snail		 Spider Sea
anemone		 Insect Other All
Ryanodine receptor RyR1 image image image - - - - - image
Ryanodine receptor RyR2 image - image - - - - - image
Ryanodine receptor RyR3 image - image - - - - - image
Ryanodine receptor All image image image - - - - - image
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Nomenclature Toxins that inhibit RyR channels are named φ (phi) toxins (see King et al., 2008).

Venom protein entries in UniProtKB/Swiss-Prot

(all links/actions below point to uniprot.org website)

31 entries grouped by family

9 entries

CRISP family

Select_allDeselect_all "CRISP family" VenomZone page
CRVP1_NAJAT Cysteine-rich venom protein natrin-1 ... Naja atra (Chinese cobra)

pdb 1XTA; 1XX5; 2GIZ; 3MZ8

CRVP1_NAJKA Cysteine-rich venom protein kaouthin-1 ... Naja kaouthia (Monocled cobra) (Naja siamensis)
CRVPA_NAJHA Cysteine-rich venom protein annuliferin-a (CRVP) Naja annulifera (Banded Egyptian cobra) (Naja ...
CRVPB_NAJHA Cysteine-rich venom protein annuliferin-b (CRVP) Naja annulifera (Banded Egyptian cobra) (Naja ...
CRVP_HELHO Cysteine-rich venom protein helothermine (CRVP ... Heloderma horridum horridum (Mexican beaded ...
CRVP_HEMHA Cysteine-rich venom protein hematin (CRVP) Hemachatus haemachatus (Rinkhals) (Sepedon ...
CRVP_NAJMO Cysteine-rich venom protein mossambin (CRVP) Naja mossambica (Mozambique spitting cobra)
CRVP_OVOOK Cysteine-rich venom protein okinavin (CRVP) Ovophis okinavensis (Ryukyu Island pit viper) ...
CRVP_PROMU Cysteine-rich venom protein (TM-CRVP) Protobothrops mucrosquamatus (Taiwan habu) ...

2 entries

Not in a family

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LAIT1_LIOAU Insecticidal toxin LaIT1 Liocheles australasiae (Dwarf wood scorpion)

pdb 2LDS

TXS2B_HORWA Phi-liotoxin-Lw1a (Phi-LITX-Lw1a) ... Hormurus waigiensis (Australian rainforest ...

pdb 2KYJ

5 entries

Phospholipase A2 family, Group III subfamily

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IPTXI_PANIM Phospholipase A2 imperatoxin-1 (Imperatoxin I) ... Pandinus imperator (Emperor scorpion)
PA2_CHEFU Phospholipase A2 large subunit (HfPLA2) (EC ... Chersonesometrus fulvipes (Indian black ...
PA2_HETLA Phospholipase A2 heteromtoxin (HmTx) [Cleaved ... Heterometrus laoticus (Thai giant scorpion)
PA2_HOFGE Phospholipase A2 (HgPLA2) (EC 3.1.1.4) (Group ... Hoffmannihadrurus gertschi (Scorpion) (Hadrurus ...
PA2_HOTTA Phospholipase A2 (MtsPLA2) [Cleaved into: Large ... Hottentotta tamulus (Eastern Indian scorpion) ...

9 entries

Scorpion calcin family

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CAHAD_HOFGE Hadrucalcin (HdCa) Hoffmannihadrurus gertschi (Scorpion) (Hadrurus ...
CAHEM_HEMLE Hemicalcin (HCa) (HmCa) Hemiscorpius lepturus (Scorpion)
CAIMP_PANIM Imperacalcin (IpCa) (Imperatoxin activator) ... Pandinus imperator (Emperor scorpion)

pdb 1IE6; 8DTB; 8DUJ

CAINT_THOIN Intrepicalcin (ViCaTx1) Thorellius intrepidus (Scorpion) (Vaejovis ...
CAMAU_SCOPA Maurocalcin (MCa) (Maurocalcine) Scorpio palmatus (Israeli golden scorpion) ...

pdb 1C6W

CAOP1_OPICA Opicalcin-1 (OpCa1) (Opicalcine-1) Opistophthalmus carinatus (African yellow leg ...
CAOP2_OPICA Opicalcin-2 (OpCa2) (Opicalcine-2) Opistophthalmus carinatus (African yellow leg ...
CAURO_UROYA Urocalcin (UrCa) (Calcium-channel toxin-like 20) Urodacus yaschenkoi (Inland robust scorpion)
CAVEJ_VAEME Vejocalcin (VjCa) Vaejovis mexicanus (Mexican scorpion)

3 entries

Scorpion calcin-like family

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CL758_BUTIS Putative calcium channel toxin Tx758 Buthus israelis (Israeli scorpion) (Buthus ...
CLCA1_MESMA Toxin BmCa-1 (BmKCaTx4) (Calcium channel toxin ... Mesobuthus martensii (Manchurian scorpion) ...
CLML_MESEU Neurotoxin lambda-MeuTx (Calcium channel ... Mesobuthus eupeus (Lesser Asian scorpion) ...

pdb 8F2F

1 entry

Scorpion calcin-like family, KTX subfamily

CLKTX_LYCMC Putative calcium channel toxin 196 Lychas mucronatus (Chinese swimming scorpion)

2 entries

Short scorpion toxin superfamily, Potassium channel inhibitor family, Alpha-KTx 09 subfamily

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KAX96_HOTJU Potassium channel toxin alpha-KTx 9.6 (BjTx-1) Hottentotta judaicus (Black scorpion) (Buthotus ...
KAX97_HOTJU Potassium channel toxin alpha-KTx 9.7 (BjTx-2) Hottentotta judaicus (Black scorpion) (Buthotus ...