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UniProtKB/Swiss-Prot P51787: Variant p.Arg555Cys

Potassium voltage-gated channel subfamily KQT member 1
Gene: KCNQ1
Variant information

Variant position:  555
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Disease [Disclaimer]
The variants are classified into three categories: Disease, Polymorphism and Unclassified.
  • Disease: Variants implicated in disease according to literature reports.
  • Polymorphism: Variants not reported to be implicated in disease.
  • Unclassified: Variants with uncertain implication in disease according to literature reports. Evidence against or in favor of a pathogenic role is limited and/or conflicting.

Residue change:  From Arginine (R) to Cysteine (C) at position 555 (R555C, p.Arg555Cys).
Indicates the amino acid change of the variant. The one-letter and three-letter codes for amino acids used in UniProtKB/Swiss-Prot are those adopted by the commission on Biochemical Nomenclature of the IUPAC-IUB.

Physico-chemical properties:  Change from large size and basic (R) to medium size and polar (C)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  -3
The score within a Blosum matrix for the corresponding wild-type to variant amino acid change. The log-odds score measures the logarithm for the ratio of the likelihood of two amino acids appearing by chance. The Blosum62 substitution matrix is used. This substitution matrix contains scores for all possible exchanges of one amino acid with another:
  • Lowest score: -4 (low probability of substitution).
  • Highest score: 11 (high probability of substitution).
More information can be found on the following page

Involvement in disease:  Long QT syndrome 1 (LQT1) [MIM:192500]: A heart disorder characterized by a prolonged QT interval on the ECG and polymorphic ventricular arrhythmias. They cause syncope and sudden death in response to exercise or emotional stress, and can present with a sentinel event of sudden cardiac death in infancy. {ECO:0000269|PubMed:10024302, ECO:0000269|PubMed:10220144, ECO:0000269|PubMed:10220146, ECO:0000269|PubMed:10367071, ECO:0000269|PubMed:10409658, ECO:0000269|PubMed:10482963, ECO:0000269|PubMed:10728423, ECO:0000269|PubMed:10973849, ECO:0000269|PubMed:11799244, ECO:0000269|PubMed:12442276, ECO:0000269|PubMed:15840476, ECO:0000269|PubMed:16414944, ECO:0000269|PubMed:16922724, ECO:0000269|PubMed:18165683, ECO:0000269|PubMed:18400097, ECO:0000269|PubMed:19540844, ECO:0000269|PubMed:19716085, ECO:0000269|PubMed:19808498, ECO:0000269|PubMed:21241800, ECO:0000269|PubMed:24184248, ECO:0000269|PubMed:24269949, ECO:0000269|PubMed:24713462, ECO:0000269|PubMed:25037568, ECO:0000269|PubMed:25139741, ECO:0000269|PubMed:25705178, ECO:0000269|PubMed:8528244, ECO:0000269|PubMed:8818942, ECO:0000269|PubMed:8872472, ECO:0000269|PubMed:9024139, ECO:0000269|PubMed:9272155, ECO:0000269|PubMed:9302275, ECO:0000269|PubMed:9312006, ECO:0000269|PubMed:9323054, ECO:0000269|PubMed:9386136, ECO:0000269|PubMed:9482580, ECO:0000269|PubMed:9570196, ECO:0000269|PubMed:9641694, ECO:0000269|PubMed:9693036, ECO:0000269|PubMed:9702906, ECO:0000269|PubMed:9799083, ECO:0000269|PubMed:9927399, ECO:0000269|Ref.31}. Note=The disease is caused by mutations affecting the gene represented in this entry.
The name and a short description of the disease associated with the variant. For more information about the disease, the user can refer to OMIM, following the link provided after the disease acronym.

Variant description:  In LQT1; associated with a fruste phenotype; decreases interaction with KCNE1 C-terminus; does not affect plasma membrane localization; reduces IKS current density; shifts activation of the voltage dependence; deactivates more rapidly; impairs binding with phosphatidylinositol 4,5-bisphosphate.
Any additional useful information about the variant.

Other resources:  
Links to websites of interest for the variant.



Sequence information

Variant position:  555
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  676
The length of the canonical sequence.

Location on the sequence:   PYDVRDVIEQYSQGHLNLMV  R IKELQRRLDQSIGKPSLFIS
The residue change on the sequence. Unless the variant is located at the beginning or at the end of the protein sequence, both residues upstream (20) and downstream (20) of the variant will be shown.

Residue conservation: 
The multiple alignment of the region surrounding the variant against various orthologous sequences.

Human                         PYDVRDVIEQYSQGHLNLMVRIKELQRRLDQSIGKPSLFIS

Mouse                         PYDVRDVIEQYSQGHLNLMVRIKELQRRLDQSIGKPSLFIP

Rat                           PYDVRDVIEQYSQGHLNLMVRIKELQRRLDQSIGKPSLFIP

Rabbit                        PYDVRDVIEQYSQGHLNLMVRIKELQRRLDQSIGKPSLFVP

Xenopus laevis                PYDVRDVIEQYSQGHLNLMVRIKELQRRLDQSLGKPSLFLS

Sequence annotation in neighborhood:  
The regions or sites of interest surrounding the variant. In general the features listed are posttranslational modifications, binding sites, enzyme active sites, local secondary structure or other characteristics reported in the cited references. The "Sequence annotation in neighborhood" lines have a fixed format:
  • Type: the type of sequence feature.
  • Positions: endpoints of the sequence feature.
  • Description: contains additional information about the feature.

TypePositionsDescription
Chain 1 – 676 Potassium voltage-gated channel subfamily KQT member 1
Topological domain 349 – 676 Cytoplasmic
Region 535 – 572 Interaction with KCNE1 C-terminus
Helix 538 – 566


Literature citations

Properties of KvLQT1 K+ channel mutations in Romano-Ward and Jervell and Lange-Nielsen inherited cardiac arrhythmias.
Chouabe C.; Neyroud N.; Guicheney P.; Lazdunski M.; Romey G.; Barhanin J.;
EMBO J. 16:5472-5479(1997)
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1); FUNCTION; CHARACTERIZATION OF VARIANT LQT1 CYS-555;

Compendium of cardiac channel mutations in 541 consecutive unrelated patients referred for long QT syndrome genetic testing.
Tester D.J.; Will M.L.; Haglund C.M.; Ackerman M.J.;
Heart Rhythm 2:507-517(2005)
Cited for: VARIANTS LQT1 71-ALA--PRO-73 DEL; THR-73; GLY-115; TYR-122; ILE-133; PHE-136; LYS-160; ARG-168; CYS-174; GLN-190; PHE-204; LEU-225; ASN-235; ASN-242; CYS-243; MET-254; 254-VAL--PHE-256 DEL; CYS-259; LEU-259; ASP-261; PRO-266; SER-269; ASP-269; PHE-273; ARG-273; SER-276 DEL; LEU-277; HIS-278; LYS-290; ASP-292; CYS-293; VAL-302; ARG-304; SER-305; ILE-312; SER-314; ARG-314; ASP-314; CYS-315; ARG-316; ALA-322; PHE-339 DEL; VAL-341; SER-343; GLU-344; VAL-344; GLU-345; TRP-349; PRO-353; ARG-362; TRP-366; HIS-374; SER-380; TYR-389; TRP-452; GLY-524; GLU-526; TRP-539; LEU-546; CYS-555; HIS-555; TYR-566; SER-567; ARG-568; MET-587; THR-590; HIS-591; GLN-594; MET-619 AND SER-626;

Spectrum and prevalence of mutations from the first 2,500 consecutive unrelated patients referred for the FAMILION long QT syndrome genetic test.
Kapplinger J.D.; Tester D.J.; Salisbury B.A.; Carr J.L.; Harris-Kerr C.; Pollevick G.D.; Wilde A.A.; Ackerman M.J.;
Heart Rhythm 6:1297-1303(2009)
Cited for: VARIANTS LQT1 VAL-2; SER-7; THR-46; 64-PRO--PRO-70 DEL; PHE-66; THR-73; CYS-111; LEU-117; LEU-127; ILE-133; PRO-134; ALA-144; MET-153; MET-162; ARG-168; MET-172; CYS-174; HIS-174; THR-178; SER-179; HIS-184; ARG-186; GLN-190; LEU-190; TRP-195; VAL-198; ALA-199; MET-204; MET-215; MET-224; LEU-225; CYS-231; HIS-231; ASN-235; GLY-241; ASN-242; CYS-243; PRO-250; MET-254; CYS-259; LEU-259; VAL-262; PRO-266; SER-268; ASP-269; SER-269; ASP-272; PHE-273; VAL-274; LEU-277; PRO-277; GLU-280; CYS-281; PRO-282; GLY-283; ASP-292; CYS-293; GLU-302; VAL-302; PRO-303; ARG-305; SER-305; ARG-306; ILE-312; CYS-314; SER-314; CYS-315; VAL-316; SER-320; ALA-322; MET-322; ARG-325; TYR-339; GLU-341; GLY-341; VAL-341; PHE-342; LEU-343; ARG-350; SER-351; ARG-354; MET-360; ARG-362; HIS-365; GLN-366; TRP-366; HIS-374; GLY-379; LYS-385; PRO-389; THR-391 INS; TRP-397; ARG-398; GLU-446; LEU-448; TRP-451; SER-460; LEU-477; TRP-511; GLN-518; ARG-520; SER-522; GLY-524; THR-525; VAL-525; TRP-533; GLN-539; TRP-539; ILE-541; LYS-543; LEU-546; ARG-547; CYS-555; HIS-555; SER-555; GLU-557; PHE-566; PRO-566; TYR-566; THR-567; ARG-568; GLU-569; LEU-571; MET-587; ASP-589; CYS-591; HIS-591; GLN-594; PRO-594; GLU-596 DEL; LYS-596; MET-600; ASN-611; HIS-614 DEL; SER-626 AND ARG-635;

Long QT mutations at the interface between KCNQ1 helix C and KCNE1 disrupt I(KS) regulation by PKA and PIP(2).
Dvir M.; Strulovich R.; Sachyani D.; Ben-Tal Cohen I.; Haitin Y.; Dessauer C.; Pongs O.; Kass R.; Hirsch J.A.; Attali B.;
J. Cell Sci. 127:3943-3955(2014)
Cited for: CHARACTERIZATION OF VARIANTS LQT1 LEU-546; CYS-555; HIS-555; GLU-557 AND ASP-589; INTERACTION WITH KCNE1 AND AKAP9; SUBCELLULAR LOCATION; FUNCTION;

Disclaimer: Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. They are not in any way intended to be used as a substitute for professional medical advice, diagnostic, treatment or care.