同: Sarcoendoplasmic reticulum calcium ATPase

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/05/25 14:24:07」(JST)

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SERCA, or sarco/endoplasmic reticulum Ca²⁺-ATPase, or SR Ca²⁺-ATPase, is a calcium ATPase-type P-ATPase.

Function

SERCA resides in the sarcoplasmic reticulum (SR) within muscle cells. It is a Ca²⁺ ATPase that transfers Ca²⁺ from the cytosol of the cell to the lumen of the SR at the expense of ATP hydrolysis during muscle relaxation.

There are 3 major domains on the cytoplasmic face of SERCA: the phosphorylation and nucleotide-binding domains, which form the catalytic site, and the actuator domain, which is involved in the transmission of major conformational changes.

It seems that, in addition to the calcium-transporting properties, SERCA1 generates heat in some adipocytes.^[1]^[2]

Regulation

The rate at which SERCA moves Ca²⁺ across the SR membrane can be controlled by the regulatory protein phospholamban (PLB/PLN). SERCA is normally inhibited by PLB, with which it is closely associated. Increased β-adrenergic stimulation reduces the association between SERCA and PLB by the phosphorylation of PLB by PKA.^[3] When PLB is associated with SERCA, the rate of Ca²⁺ movement is reduced; upon dissociation of PLB, Ca²⁺ movement increases.

Another protein, calsequestrin, binds calcium within the SR and helps to reduce the concentration of free calcium within the SR, which assists SERCA so that it does not have to pump against such a high concentration gradient. The SR has a much higher concentration of Ca²⁺ (10,000x) inside when compared to the intracellular Ca²⁺ concentration. SERCA2 can be regulated by microRNAs, for instance miR-25 suppresses SERCA2 in heart failure.

For experimental reasons, SERCA can be inhibited by thapsigargin and induced by istaroxime.

Paralogs

There are 3 major paralogs, SERCA1-3, which are expressed at various levels in different cell types.

ATP2A1 - SERCA1
ATP2A2 - SERCA2
ATP2A3 - SERCA3

There are additional post-translational isoforms of both SERCA2 and SERCA3, which serve to introduce the possibility of cell-type-specific Ca²⁺-reuptake responses as well as increasing the overall complexity of the Ca²⁺ signaling mechanism.

References

^ de Meis L, Oliveira GM, Arruda AP, Santos R, Costa RM, Benchimol M (2005). "The thermogenic activity of rat brown adipose tissue and rabbit white muscle Ca2+-ATPase". IUBMB Life 57 (4–5): 337–45. doi:10.1080/15216540500092534. PMID 16036618.
^ Arruda AP, Nigro M, Oliveira GM, de Meis L (June 2007). "Thermogenic activity of Ca2+-ATPase from skeletal muscle heavy sarcoplasmic reticulum: the role of ryanodine Ca2+ channel". Biochim. Biophys. Acta 1768 (6): 1498–505. doi:10.1016/j.bbamem.2007.03.016. PMID 17466935.
^ MacLennan, David H.; Kranias, Evangelia G. (July 2003). "Phospholamban: a crucial regulator of cardiac contractility". Nature Reviews Molecular Cell Biology 4 (7): 566–577. doi:10.1038/nrm1151. |accessdate= requires |url= (help)

External links

Sarcoplasmic Reticulum Calcium-Transporting ATPases at the US National Library of Medicine Medical Subject Headings (MeSH)

http://en.m.wikipedia.org/wiki/Mir-25_microRNA_precursor_family

UpToDate Contents

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1. 悪性高熱症：臨床診断および急性期のマネージメント malignant hyperthermia clinical diagnosis and management of acute crisis
2. 心不全および心筋梗塞における遺伝子療法および細胞療法 genetic and cellular therapy in heart failure and myocardial infarction

English Journal

Characterization of sarcoplasmic calcium binding protein (SCP) variants from freshwater crayfish Procambarus clarkii.

White AJ, Northcutt MJ, Rohrback SE, Carpenter RO, Niehaus-Sauter MM, Gao Y, Wheatly MG, Gillen CM.SourceDepartment of Biology, Kenyon College, Gambier, OH 43022, USA.
Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology.Comp Biochem Physiol B Biochem Mol Biol.2011 Sep;160(1):8-14. Epub 2011 Apr 15.
Sarcoplasmic calcium binding protein (SCP) is an invertebrate EF-hand calcium buffering protein that has been proposed to fulfill a similar function in muscle relaxation as vertebrate parvalbumin. We have identified three SCP variants in the freshwater crayfish Procambarus clarkii. The variants (pcS
PMID 21530674

Calcium homoeostasis modulator 1 (CALHM1) reduces the calcium content of the endoplasmic reticulum (ER) and triggers ER stress.

Gallego-Sandin S, Alonso MT, Garcia-Sancho J.SourceInstituto de Biologia y Genetica Molecular (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Cientificas (CSIC), C/ Sanz y Fores, 3, 47003-Valladolid, Spain.
The Biochemical journal.Biochem J.2011 Aug 1;437(3):469-75.
CALHM1 (calcium homoeostasis modulator 1), a membrane protein with similarity to NMDA (N-methyl-D-aspartate) receptor channels that localizes in the plasma membrane and the ER (endoplasmic reticulum) of neurons, has been shown to generate a plasma-membrane Ca2+ conductance and has been proposed to i
PMID 21574960

Japanese Journal

Evaluation of left ventricular mechanical work and energetics of normal hearts in SERCA2a transgenic rats

Zhang Guo-Xing,Obata Koji,Takeshita Daisuke [他]
The journal of physiological sciences 62(3), 221-231, 2012-05
NAID 40019242746

ラット脳カルシウムATPase活性の静脈麻酔薬による抑制

田仲宏光,出山義昭,吉村善隆,鈴木邦明,福島和昭
北海道歯学雑誌 32(2), 222-229, 2012-03
… た（Ca-ATPase活性）．PⅠのCa-ATPase活性はpropofol濃度に依存して抑制され50％阻害濃度（Ki0.5）は0.25 mMであった．Propofol存在下でCa-ATPase活性のCa濃度依存性を調べると，存在するpropofol濃度に依存して最大活性とCaに対するKmは低下した．PⅡ及びPⅢには，ウェスタンブロッティング及び酵素学的性質からCa,Mg-ATPaseであるPMCA（plasma membrane Ca-ATPase）及びSERCA（sarcoendoplasmic reticulum Ca-ATPase）の存在が明らかになった．PⅡ …
NAID 120003918970

「筋小胞体カルシウムATPアーゼ」

　　[★]

英: sarcoplasmic reticulum calcium ATPase sarcoplasmic reticulum Ca2+-ATPase, SERCA
関: 筋小胞体カルシウムポンプ、筋小胞体カルシウム輸送ATPアーゼ、筋小胞体Ca2+/ATPアーゼ

「sarcoplasmic reticulum Ca2+-ATPase」

　　[★]

筋小胞体カルシウムATPアーゼ、筋小胞体Ca2+/ATPアーゼ

関: sarcoplasmic reticulum calcium ATPase、sarcoplasmic reticulum calcium-transporting ATPase、SERCA

「sarcoplasmic reticulum calcium ATPase」

　　[★]

筋小胞体カルシウムATPアーゼ

関: sarcoplasmic reticulum Ca2+-ATPase、sarcoplasmic reticulum calcium-transporting ATPase、SERCA

「sarcoplasmic reticulum calcium pump」

　　[★]

筋小胞体カルシウム・ンプ

関: SERCA

「SER」

　　[★]

[1] Meis L, Oliveira GM, Arruda AP, Santos R, Costa RM, Benchimol M (2005). "The thermogenic activity of rat brown adipose tissue and rabbit white muscle Ca2+-ATPase". IUBMB Life 57 (4–5): 337–45. doi:10.1080/15216540500092534. PMID 16036618.

[2] Arruda AP, Nigro M, Oliveira GM, de Meis L (June 2007). "Thermogenic activity of Ca2+-ATPase from skeletal muscle heavy sarcoplasmic reticulum: the role of ryanodine Ca2+ channel". Biochim. Biophys. Acta 1768 (6): 1498–505. doi:10.1016/j.bbamem.2007.03.016. PMID 17466935.

[3] MacLennan, David H.; Kranias, Evangelia G. (July 2003). "Phospholamban: a crucial regulator of cardiac contractility". Nature Reviews Molecular Cell Biology 4 (7): 566–577. doi:10.1038/nrm1151. |accessdate= requires |url= (help)

リンク元	「筋小胞体カルシウムATPアーゼ」「sarcoplasmic reticulum Ca2+-ATPase」「sarcoplasmic reticulum calcium ATPase」「sarcoplasmic reticulum calcium pump」
関連記事	「SER」

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SERCA