Centrins, also known as caltractins, are a family of

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

-binding

phosphoprotein A phosphoprotein is a protein that is posttranslationally modified by the attachment of either a single phosphate group, or a complex molecule such as 5'-phospho-DNA, through a phosphate group. The target amino acid is most often serine, threonin ...

s found in the

centrosome In cell biology, the centrosome (Latin centrum 'center' + Greek sōma 'body') (archaically cytocentre) is an organelle that serves as the main microtubule organizing center (MTOC) of the animal cell, as well as a regulator of cell-cycle progres ...

eukaryote Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

s. Centrins are present in the

centriole In cell biology a centriole is a cylindrical organelle composed mainly of a protein called tubulin. Centrioles are found in most eukaryotic cells, but are not present in conifers (Pinophyta), flowering plants (angiosperms) and most fungi, and a ...

s and pericentriolar lattice. Human centrin genes are

CETN1 Centrin-1 is a protein that in humans is encoded by the ''CETN1'' gene. It belongs to the centrin Centrins, also known as caltractins, are a family of calcium-binding phosphoproteins found in the centrosome of eukaryotes. Centrins are present in ...

CETN2 Centrin-2 is a protein that in humans is encoded by the ''CETN2'' gene. It belongs to the centrin family of proteins. Centrin-2 belongs to a family of calcium-binding proteins and is a structural component of the centrosome. The high level of co ...

and

CETN3 Centrin-3 is a protein that in humans is encoded by the ''CETN3'' gene. It belongs to the centrin Centrins, also known as caltractins, are a family of calcium-binding phosphoproteins found in the centrosome of eukaryotes. Centrins are present i ...

History

Centrin was first isolated and characterized from the flagellar roots of the green alga ''

Tetraselmis striata ''Tetraselmis'' is a genus of phytoplankton. ''Tetraselmis'' is a green algal genus within the order Chlorodendrales, and they are characterized by their intensely-colored green chloroplast, their flagellated cell bodies, the presence of a pyren ...

'' in 1984.

Function

Centrins are required for duplication of centrioles. They may also play a role in severing of

microtubule Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nm and have an inner diameter between 11 an ...

s by causing calcium-mediated contraction. The majority of centrin in the cell is non-centrosomal whose function is not yet clear.

Structure

Centrin belongs to the

EF-hand The EF hand is a helix–loop–helix structural domain or ''motif'' found in a large family of calcium-binding proteins. The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, in ...

superfamily of calcium-binding proteins and has four calcium-binding EF-hands. It has a molecular weight of 20 kDa.

References

Protein families {{protein-stub

History

Function

Structure

See also

References