Pericentriolar material

Abstract

The pericentriolar material (PCM) refers to the proteinaceous material that surrounds the centrioles -two small microtubule-based cylindersand with them constitutes the centrosome, the main microtubuleorganizing center (MTOC) found in animal cells. Amongst other functions, centrosomes regulate cell shape, polarity and spindle pole organization.In the fi rst studies, where centrosomes were analyzed by electron microscopy, the PCM was described as an amorphous electronopaque material that is the site of origin of centrosomal microtubules. Biochemical and immunocytological characterization of the PCM led to the identifi cation of its major components in different model organisms, including yeasts and other fungi, worms and fl ies. These include, amongst others, pericentrin (PCNT)/D-PLP (human/Drosophila), Cep192/SPD-2 (human/Drosophila), CDK5RAP2/ CNN (human/Drosophila), SPD-5 in Caenorhabditis elegans, Cep152/ Asterless (Asl) (human/Drosophila), CPAP/Sas4 (human/Drosophila) and -tubulin. These proteins show an abundance of coiled-coiled domains that mediate proteinprotein interactions and provide a scaffold onto which key regulators of centrosome function are recruited.More recently, advances in imaging techniques, such as subdiffractional super-resolution imaging, showed that the PCM does actually have an organized architecture, forming annular concentric rings of components extending approximately 150-200 nm from the surface of the centriole. Recent work suggests that, as the PCM accumulates and expands upon mitotic entry, it is less organized and acquires gel-like properties that favor the concentration of proteins required for microtubule nucleation.

The 3D architecture and molecular foundations ofde novocentriole assemblyviabicentrioles

“…6Ab). Consequently, we hypothesize that the LS may perform PCM-like functions in concentrating components and/or stabilizing the structures assembled (Pimenta-Marques and Bettencourt-Dias, 2020), such as the naked cartwheel and particular MT triplets. In the future it will be important to be able to manipulate the MLS, as well as to identify PCM-functional equivalents, to test whether these are critical variables in generating diverse structures, such as the ones observed here in P. patens .…”

The 3D architecture and molecular foundations of de novo centriole assembly via bicentrioles

“…The LS contains centrin, 58 SAS6 (Figure 4H), and perhaps g-tubulin2 (Figure 6C). Consequently, we believe that the LS may perform PCM-like functions in component concentration and/or structural stability, 59 namely of the naked cartwheels. However, while the PCM is ultrastructurally amorphous, 60 the LS is composed of organized proteinaceous layers (Figures 2J, 3I, and 3L), resembling the basal bodies striated fibers.…”

Ana1/CEP295 is an essential player in the centrosome maintenance program regulated by Polo kinase

“…The PCM is indispensable for centriole biogenesis and for nucleating and anchoring MTs at the centrosome (Pimenta-Marques and Bettencourt-Dias, 2020). Centrioles are small microtubule (MT) cylinders with a striking 9-fold radial symmetry of doublets or triplets of MTs that build up the centriole wall (Fig.…”

“…This organelle is composed of two centrioles, surrounded by a multiprotein matrix called the pericentriolar material (PCM) (Brito, Gouveia and Bettencourt-Dias, 2012; Conduit, Wainman and Raff, 2015). The PCM is indispensable for centriole biogenesis and for nucleating and anchoring MTs at the centrosome (Pimenta-Marques and Bettencourt-Dias, 2020). Centrioles are small microtubule (MT) cylinders with a striking 9-fold radial symmetry of doublets or triplets of MTs that build up the centriole wall (Fig.…”