Pericentriolar material (PCM, sometimes also called pericent matrix) is a highly structured, dense mass of protein which makes up the part of the animal centrosome that surrounds the two

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. The PCM contains proteins responsible for

microtubule nucleation In cell biology, microtubule nucleation is the event that initiates '' de novo'' formation of microtubules (MTs). These filaments of the cytoskeleton typically form through polymerization of α- and β-tubulin dimers, the basic building blocks of th ...

and

anchoring An anchor is a device, normally made of metal , used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ''ancora'', which itself comes from the Greek ἄγ ...

including γ-tubulin, pericentrin and

ninein Ninein is a protein that in humans is encoded by the ''NIN'' gene. Ninein, together with its paralog Ninein-like protein is one of the proteins important for centrosomal function. This protein is important for positioning and anchoring the micro ...

Although the PCM appears amorphous by

electron microscopy An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a hi ...

, super-resolution microscopy finds that it is highly organized. The PCM have 9-fold symmetry that mimics the symmetry of the

. Some PCM proteins are organized such that one end of the protein is found near the centriole and the other end is farther away from the centriole. The PCM size is dynamic during the cell cycle. After cell division, the PCM size is reduced in a process named centrosome reduction.Atypical centrioles during sexual reproduction Tomer Avidor-Reiss*, Atul Khire, Emily L. Fishman and Kyoung H. Jo Curr Biol. 2015 Nov 16;25(22):2956-63. doi: 10.1016/j.cub.2015.09.045. Epub 2015 Oct 17. http://journal.frontiersin.org/article/10.3389/fcell.2015.00021/full During the G2 phase of the cell cycle, the PCM grows in size in a process named centrosome maturation. According to the Gene Ontology, the following human proteins are associated with the PC

* BBS4, Bardet-Biedl syndrome 4 protein * Lck, Proto-oncogene tyrosine-protein kinase LCK * PCM1, Pericentriolar material 1 protein * TNKS, Tankyrase-1 * TNKS2, Tankyrase-2 * TUBE1, Tubulin epsilon chain * PCNT, pericentrin, a matrix scaffold protein *

CDK5RAP2 CDK5 regulatory subunit-associated protein 2 is a protein that in humans is encoded by the ''CDK5RAP2'' gene. It has necessary roles in the formation and stability of microtubules from the centrosome and has been found to be linked to human brain ...

, cyclin dependant kinase receptor associated protein 2, binds gTubRCs that nucleate

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 * NEDD1, binds gTubRCs that stabilise microtubules *

Gamma Tubulin Tubulin in molecular biology can refer either to the tubulin protein superfamily of globular proteins, or one of the member proteins of that superfamily. α- and β-tubulins polymerize into microtubules, a major component of the eukaryotic cytos ...

, nucleates microtubules

References

Cell biology {{Cell-biology-stub