P31235 (CASQ2_RABIT) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Calsequestrin-2

Alternative name(s):
Calsequestrin, cardiac muscle isoform

Gene names

Name:

CASQ2

Organism

Oryctolagus cuniculus (Rabbit) [Reference proteome]

Taxonomic identifier

9986 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Deuterostomia › Chordata › Craniata › Vertebrata › Gnathostomata › Teleostomi › Euteleostomi › Sarcopterygii › Tetrapoda › Amniota › Mammalia › Theria › Eutheria › Euarchontoglires › Glires › Lagomorpha › Leporidae › Oryctolagus

Protein attributes

Sequence length	409 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Calsequestrin is a high-capacity, moderate affinity, calcium-binding protein and thus acts as an internal calcium store in muscle. The release of calcium bound to calsequestrin through a calcium release channel triggers muscle contraction. The skeletal muscle CASQ1) binds around 80 Ca2+ ions, while the cardiac CASQ2) binds approximately 60 Ca2+ ions.
Subunit structure	Monomer, homodimer and homooligomer. Mostly monomeric in the absence of calcium. Forms higher oligomers in a calcium-dependent manner. Dimers associate to form tetramers, that then form linear homopolymer chains By similarity.
Subcellular location	Sarcoplasmic reticulum lumen. Note: This isoform of calsequestrin occurs in the sarcoplasmic reticulum's terminal cisternae luminal spaces of cardiac and slow skeletal muscle cells.
Post-translational modification	Phosphorylation in the C-terminus, probably by CK2, moderately increases calcium buffering capacity By similarity.
Sequence similarities	Belongs to the calsequestrin family.

Ontologies

Keywords
Cellular component	Sarcoplasmic reticulum
Domain	Signal
Ligand	Calcium
Molecular function	Muscle protein
PTM	Glycoprotein Phosphoprotein
Technical term	Complete proteome Direct protein sequencing Reference proteome
Gene Ontology (GO)
Cellular_component	sarcoplasmic reticulum lumen Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular_function	calcium ion binding Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Signal peptide	1 – 19	19	Ref.2
	Chain	20 – 409	390	Calsequestrin-2		PRO_0000004220
Regions
	Compositional bias	373 – 409	37	Asp/Glu-rich (acidic)
Amino acid modifications
	Modified residue	404	1	Phosphoserine By similarity
	Glycosylation	335	1	N-linked (GlcNAc...) Potential
Experimental info
	Sequence conflict	45	1	I → S AA sequence Ref.2

Sequences

	Sequence		Length	Mass (Da)
	P31235 [UniParc]. Last modified July 1, 1993. Version 1. Checksum: 068D469EA7457DAE	FASTA	409	47,357
	10 20 30 40 50 60 MKRAHLFVVG VYLLSSCRAE EGLNFPTYDG KDRVVSLSEK NFKQILKKYD LLCLYYHAPV 70 80 90 100 110 120 SADKVAQKQF QLKEIVLELV AQVLEHKEIG FVMVDAKKEA KLAKKLGFDE EGSLYILKGD 130 140 150 160 170 180 RTIEFDGEFA ADVLVEFLLD LIEDPVEIIN SKLEVQAFER IEDHIKLIGF FKSADSEYYK 190 200 210 220 230 240 AFEEAAEHFQ PYIKFFATFD KGVAKKLSLK MNEVDFYEPF MDEPTPIPNK PYTEEELVEF 250 260 270 280 290 300 VKEHQRPTLR RLRPEDMFET WEDDLNGIHI VPFAEKSDPD GYEFLEILKQ VARDNTDNPD 310 320 330 340 350 360 LSIVWIDPDD FPLLVAYWEK TFKIDLFKPQ IGVVNVTDAD SVWMEIPDDD DLPTAEELED 370 380 390 400 WIEDVLSGKI NTEDDDNEDE DDDDDNDDDD DDNGNSDEED NDDSDEDDE

References

[1]	"Cloning and characterization of the gene encoding rabbit cardiac calsequestrin." Arai M., Alpert N.R., Periasamy M. Gene 109:275-279(1991) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA]. Strain: New Zealand white.
[2]	"Characterization of cardiac calsequestrin." Slupsky J.R., Ohnishi M., Carpenter M.R., Reithmeier R.A.F. Biochemistry 26:6539-6544(1987) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE OF 20-49.

Cross-references

Sequence databases
EMBL GenBank DDBJ	X55040 mRNA. Translation: CAA38880.1.
PIR	JQ1396.
RefSeq	NP_001095161.1. NM_001101691.1.
UniGene	Ocu.3255.
3D structure databases
ProteinModelPortal	P31235.
SMR	P31235. Positions 22-370.
ModBase	Search...
Protein-protein interaction databases
STRING	9986.ENSOCUP00000009133.
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
GeneID	100009261.
Organism-specific databases
CTD	845.
Phylogenomic databases
eggNOG	NOG77804.
HOGENOM	HOG000049047.
HOVERGEN	HBG050805.
OrthoDB	EOG4W0XD8.
Family and domain databases
Gene3D	3.40.30.10. 3 hits.
InterPro	IPR001393. Calsequestrin. IPR018233. Calsequestrin_CS. IPR012336. Thioredoxin-like_fold. [Graphical view]
PANTHER	PTHR10033. PTHR10033. 1 hit.
Pfam	PF01216. Calsequestrin. 1 hit. [Graphical view]
PRINTS	PR00312. CALSEQUESTRN.
SUPFAM	SSF52833. Thiordxn-like_fd. 3 hits.
PROSITE	PS00863. CALSEQUESTRIN_1. 1 hit. PS00864. CALSEQUESTRIN_2. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

CASQ2_RABIT

Accession

Primary (citable) accession number: P31235

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 1, 1993
Last sequence update:	July 1, 1993
Last modified:	April 3, 2013
This is version 85 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program