SERCA

SERCA stands for Sarco/Endoplasmic Reticulum Ca2+-ATPase.

Function

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

Regulation

SERCA is normally somewhat inhibited by a protein, phospholamban, with which it is closely associated. 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.

The rate at which SERCA moves Ca2+ across the SR membrane can be controlled by phospholamban (PLB/PLN) under ß-adrenergic stimulation. When PLB is associated with SERCA, the rate of Ca2+ movement is reduced, upon dissociation of PLB Ca2+ movement increases.

Paralogs

There are 3 major paralogs, SERCA1-3, which are expressed at various levels in different cell types. There are additional post-translational isoforms of both SERCA2 and 3 which serve to introduce the possibility of cell type specific Ca2+-reuptake responses as well as increasing the overall complexity of the Ca2+ signalling mechanism.

External links

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Calcium (IPA: /ˈkalsiəm/) is the chemical element in the periodic table that has the symbol Ca and atomic number 20. It has an atomic mass of 40.078.
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ATPases are a class of enzymes that catalyze the decomposition of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and a free phosphate ion. This dephosphorylation reaction releases energy, which the enzyme (in most cases) harnesses to drive other chemical reactions
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muscle fiber, also spelled muscle fibre (see spelling differences), also technically known as a myocyte, is a single cell of a muscle. Muscle fibers contain many myofibrils, the contractile unit of muscles.
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The cytosol (cf. cytoplasm, which also includes the organelles) is the internal fluid of the cell, and a portion of cell metabolism occurs here. Proteins within the cytosol play an important role in signal transduction pathways and glycolysis.
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Lumen can mean:
  • Lumen (unit), the SI unit of luminous flux
  • Lumen (anatomy), the cavity or channel within a tubular structure
  • Thylakoid lumen, the inner membrane space of the chloroplast

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ATP hydrolysis is the reaction by which chemical energy that has been stored and transported in the high-energy phosphoanhydridic bonds in ATP (Adenosine triphosphate) is released, for example in the muscles, to produce work.
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Phospholamban is a 52 amino acid integral membrane protein that regulates the Ca2+ pump in cardiac muscle cells.

Dephosphorylated phospholamban interacts with the Ca2+ ATPase pump (SERCA) to lower its activity and sensitivity to Ca2+
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Identifiers
Symbol CASQ2

Entrez 845
HUGO 1513
OMIM 114251

RefSeq NM_001232
UniProt O14958
Other data

Locus Chr. 1 p13.3-p11 Calsequestrin is a calcium-binding protein of the sarcoplasmic reticulum.
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Phospholamban is a 52 amino acid integral membrane protein that regulates the Ca2+ pump in cardiac muscle cells.

Dephosphorylated phospholamban interacts with the Ca2+ ATPase pump (SERCA) to lower its activity and sensitivity to Ca2+
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Adrenergic can refer to:
  • the adjective form of adrenalin
  • adrenergic agonist
  • adrenergic antagonist
  • adrenergic receptor

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In evolutionary biology, homology is any similarity between characters that is due to their shared ancestry. There are examples in different branches of biology. Anatomical structures that perform the same function in different biological species and evolved from the same structure
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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A membrane transport protein (or simply transporter) is a protein involved in the movement of ions, small molecules, or macromolecules, such as another protein across a biological membrane.
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ion transporter, also called an ion pump, is a transmembrane protein that moves ions across a plasma membrane against their concentration gradient. Such ion pumps can use energy from a variety of sources, including ATP or the concentration gradient of another ion (sometimes
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A symporter is an integral membrane protein that is involved in active transport of two or more different molecules or ions across a phospholipid membrane such as the plasma membrane in the same direction.
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A cotransporter is an integral membrane protein that is involved in secondary active transport. It works by binding to two molecules at a time and using the gradient of one solute's concentration to force the other molecule against its gradient.
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Identifiers
Symbol SLC12A2

Entrez 6558
HUGO 10911
OMIM 600840

RefSeq NM_001046
UniProt P55011
Other data

Locus Chr. 5 q23.3 The Na-K-2Cl symporter is a carrier protein that is inhibited by loop diuretics.
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The sodium/phosphate cotransporter (or Na+-Pi cotransport) is a protein found in the proximal tubule of the nephron. It is responsible for reabsorbing phosphate that has been filtered out at the glomerulus.
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The sodium-chloride symporter is a symporter ion pump used primarily to remove sodium and chloride ions from the distal convoluted tubule of the kidney.

Pathology

A deficiency in SLC12A3 is associated with Gitelman syndrome.
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Identifiers
Symbol SLC5A2
Alt. Symbols SGLT2

Entrez 6524
HUGO 11037
OMIM 182381

RefSeq NM_003041
UniProt P31639
Other data

Locus Chr. 16 p11.
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The sodium-iodide symporter is an ion pump that transports Iodide (I-) into thyroid epithelial cells. This is an important step in the process of iodide organification and the formation of triiodothyronine (T3) and thyroxine (T4).
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The sodium-hydrogen antiporter is a protein found in the nephron of the kidney. It is primarily responsible for maintaining the balance of sodium.[1]

References

1.

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Identifiers
Symbol SLC8A2

Entrez 6543
HUGO 11069
OMIM 601901

RefSeq NM_015063
UniProt Q9UPR5
Other data

Locus Chr. 19 q13.2 The sodium-calcium exchanger (often denoted Na+/Ca2+ exchanger,
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Identifiers
Symbol SLC24A2
Alt. Symbols NCKX2

Entrez 25769
HUGO 10976
OMIM 609838

RefSeq NM_020344
UniProt Q9UI40
Other data

Locus Chr.
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Identifiers
Symbol SLC4A1AP

Entrez 22950
HUGO 13813
OMIM 602655

RefSeq NM_018158
UniProt Q9BWU0
Other data

Locus Chr. 2 p23.
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ATPases are a class of enzymes that catalyze the decomposition of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and a free phosphate ion. This dephosphorylation reaction releases energy, which the enzyme (in most cases) harnesses to drive other chemical reactions
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ATP7A (ATPase, Cu++ transporting, alpha polypeptide (Menkes syndrome)) is a human gene that provides instructions to make a protein that is important for regulating copper levels in the body. This protein is found in most tissues, but it is absent from the liver.
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Calcium ATPase is a form of P-ATPase which transfers calcium after a muscle has contracted.

General characteristics of ATPases

ATPases (or ATP synthases) are membrane-bound enzymecomplexes/ion transporters that combine the synthesis and/or hydrolysis of adenosine
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ATP2A2 is an ATPase associated with Darier's disease.

External links

  • MeSH ATP2A2+protein,+human


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