ID   CASQ2_RABIT             Reviewed;         409 AA.
AC   P31235;
DT   01-JUL-1993, integrated into UniProtKB/Swiss-Prot.
DT   01-JUL-1993, sequence version 1.
DT   03-AUG-2022, entry version 116.
DE   RecName: Full=Calsequestrin-2;
DE   AltName: Full=Calsequestrin, cardiac muscle isoform;
DE   Flags: Precursor;
GN   Name=CASQ2;
OS   Oryctolagus cuniculus (Rabbit).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Euarchontoglires; Glires; Lagomorpha; Leporidae; Oryctolagus.
OX   NCBI_TaxID=9986;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   STRAIN=New Zealand white;
RX   PubMed=1662658; DOI=10.1016/0378-1119(91)90621-h;
RA   Arai M., Alpert N.R., Periasamy M.;
RT   "Cloning and characterization of the gene encoding rabbit cardiac
RT   calsequestrin.";
RL   Gene 109:275-279(1991).
RN   [2]
RP   PROTEIN SEQUENCE OF 20-49, AND TISSUE SPECIFICITY.
RX   PubMed=3427023; DOI=10.1021/bi00394a038;
RA   Slupsky J.R., Ohnishi M., Carpenter M.R., Reithmeier R.A.F.;
RT   "Characterization of cardiac calsequestrin.";
RL   Biochemistry 26:6539-6544(1987).
CC   -!- FUNCTION: Calsequestrin is a high-capacity, moderate affinity, calcium-
CC       binding protein and thus acts as an internal calcium store in muscle.
CC       Calcium ions are bound by clusters of acidic residues at the protein
CC       surface, especially at the interface between subunits. Can bind around
CC       60 Ca(2+) ions. Regulates the release of lumenal Ca(2+) via the calcium
CC       release channel RYR2; this plays an important role in triggering muscle
CC       contraction. Plays a role in excitation-contraction coupling in the
CC       heart and in regulating the rate of heart beats.
CC       {ECO:0000250|UniProtKB:O09161}.
CC   -!- SUBUNIT: Monomer, homodimer and homooligomer. Mostly monomeric in the
CC       absence of calcium. Forms higher oligomers in a calcium-dependent
CC       manner. Dimers associate to form tetramers, that then form linear
CC       homomer chains. Interacts with ASPH and TRDN (By similarity).
CC       {ECO:0000250|UniProtKB:O14958}.
CC   -!- SUBCELLULAR LOCATION: Sarcoplasmic reticulum lumen
CC       {ECO:0000250|UniProtKB:O09161}. Note=This isoform of calsequestrin
CC       occurs in the sarcoplasmic reticulum's terminal cisternae luminal
CC       spaces of cardiac and slow skeletal muscle cells.
CC       {ECO:0000250|UniProtKB:O09161}.
CC   -!- TISSUE SPECIFICITY: Detected in heart muscle (at protein level).
CC       {ECO:0000269|PubMed:3427023}.
CC   -!- PTM: Phosphorylation in the C-terminus, probably by CK2, moderately
CC       increases calcium buffering capacity. {ECO:0000250|UniProtKB:O14958}.
CC   -!- PTM: N-glycosylated. {ECO:0000250|UniProtKB:O14958}.
CC   -!- SIMILARITY: Belongs to the calsequestrin family. {ECO:0000305}.
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DR   EMBL; X55040; CAA38880.1; -; mRNA.
DR   PIR; JQ1396; JQ1396.
DR   RefSeq; NP_001095161.1; NM_001101691.1.
DR   AlphaFoldDB; P31235; -.
DR   SMR; P31235; -.
DR   STRING; 9986.ENSOCUP00000009133; -.
DR   GeneID; 100009261; -.
DR   KEGG; ocu:100009261; -.
DR   CTD; 845; -.
DR   eggNOG; ENOG502QU4Q; Eukaryota.
DR   InParanoid; P31235; -.
DR   OrthoDB; 1091027at2759; -.
DR   Proteomes; UP000001811; Unplaced.
DR   GO; GO:0016529; C:sarcoplasmic reticulum; IDA:CAFA.
DR   GO; GO:0033018; C:sarcoplasmic reticulum lumen; IEA:UniProtKB-SubCell.
DR   GO; GO:0014802; C:terminal cisterna; IDA:AgBase.
DR   GO; GO:0005509; F:calcium ion binding; IDA:CAFA.
DR   CDD; cd03074; PDI_b'_Calsequestrin_C; 1.
DR   CDD; cd03066; PDI_b_Calsequestrin_middle; 1.
DR   CDD; cd03065; PDI_b_Calsequestrin_N; 1.
DR   InterPro; IPR001393; Calsequestrin.
DR   InterPro; IPR041860; Calsequestrin_C.
DR   InterPro; IPR018233; Calsequestrin_CS.
DR   InterPro; IPR041858; Calsequestrin_middle_dom.
DR   InterPro; IPR041859; Calsequestrin_N.
DR   InterPro; IPR036249; Thioredoxin-like_sf.
DR   Pfam; PF01216; Calsequestrin; 1.
DR   SUPFAM; SSF52833; SSF52833; 3.
DR   PROSITE; PS00863; CALSEQUESTRIN_1; 1.
DR   PROSITE; PS00864; CALSEQUESTRIN_2; 1.
PE   1: Evidence at protein level;
KW   Calcium; Direct protein sequencing; Glycoprotein; Metal-binding;
KW   Muscle protein; Phosphoprotein; Reference proteome; Sarcoplasmic reticulum;
KW   Signal.
FT   SIGNAL          1..19
FT                   /evidence="ECO:0000269|PubMed:3427023"
FT   CHAIN           20..409
FT                   /note="Calsequestrin-2"
FT                   /id="PRO_0000004220"
FT   REGION          364..409
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        373..409
FT                   /note="Acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   MOD_RES         282
FT                   /note="Phosphotyrosine"
FT                   /evidence="ECO:0000250|UniProtKB:O09161"
FT   CARBOHYD        335
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CONFLICT        45
FT                   /note="I -> S (in Ref. 2; AA sequence)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   409 AA;  47357 MW;  068D469EA7457DAE CRC64;
     MKRAHLFVVG VYLLSSCRAE EGLNFPTYDG KDRVVSLSEK NFKQILKKYD LLCLYYHAPV
     SADKVAQKQF QLKEIVLELV AQVLEHKEIG FVMVDAKKEA KLAKKLGFDE EGSLYILKGD
     RTIEFDGEFA ADVLVEFLLD LIEDPVEIIN SKLEVQAFER IEDHIKLIGF FKSADSEYYK
     AFEEAAEHFQ PYIKFFATFD KGVAKKLSLK MNEVDFYEPF MDEPTPIPNK PYTEEELVEF
     VKEHQRPTLR RLRPEDMFET WEDDLNGIHI VPFAEKSDPD GYEFLEILKQ VARDNTDNPD
     LSIVWIDPDD FPLLVAYWEK TFKIDLFKPQ IGVVNVTDAD SVWMEIPDDD DLPTAEELED
     WIEDVLSGKI NTEDDDNEDE DDDDDNDDDD DDNGNSDEED NDDSDEDDE