Subdiffraction imaging of centrosomes reveals higher-order organizational features of pericentriolar material

Abstract

The centrosome is the main microtubule organization centre of animal cells. It is composed of a centriole pair surrounded by pericentriolar material (PCM). Traditionally described as amorphous, the architecture of the PCM is not known, although its intricate mode of assembly alludes to the presence of a functional, hierarchical structure. Here we used subdiffraction imaging to reveal organizational features of the PCM. Interphase PCM components adopt a concentric toroidal distribution of discrete diameter around centrioles. Positional mapping of multiple non-overlapping epitopes revealed that pericentrin (PCNT) is an elongated molecule extending away from the centriole. We find that PCM components occupy separable spatial domains within mitotic PCM that are maintained in the absence of microtubule nucleation complexes and further implicate PCNT and CDK5RAP2 in the organization and assembly of PCM. Globally, this work highlights the role of higher-order PCM organization in the regulation of centrosome assembly and function.

The benefits of local depletion: The centrosome as a scaffold for ubiquitin-proteasome-mediated degradation

“…12,13 Surrounding the centrioles, the interphase PCM is supported by a structured series of concentricallyarranged toroidal rings rich in coiled-coil domain scaffold proteins such as Pericentrin, Cep192, and CDK5RAP2. 14 While the substructure of the mitotic PCM is less clear, it has been demonstrated that its maturation is cued by phosphorylation of Pericentrin by the mitotic kinase Plk1 to allow further recruitment of Cep192, g-tubulin, and other core components. 12 Properly separated mature centrosomes organize the bipolar mitotic spindle to ensure proper chromosome segregation and successful cell division.…”

Exploring the evolutionary history of centrosomes

“…In animal cells, the centrosome is composed of two centrioles surrounded by the pericentriolar material (PCM). The PCM has a precise organization, which derives from the hierarchical recruitment of a small number of large coiled-coil proteins around the centrioles [3,4]. The centrioles ensure the stability and the duplication of the centrosome, whereas the PCM anchors microtubule-nucleating complexes and cell cycle regulators.…”

Centrosomal nucleolin is required for microtubule network organization

“…17,18 Indeed, several reports have lately revealed the presence of functional domains within the PCM, defined as concentric layers enclosing the mature centriole in a tube-or toroid-like arrangement. [19][20][21] The outer PCM layer contains proteins involved in microtubule nucleation such as g-tubulin. 20 Pericentrin adopts an extended conformation and is organized radially with its C terminus associated to the centriole wall and its N terminus extending toward the PCM periphery.…”

“…[19][20][21] The outer PCM layer contains proteins involved in microtubule nucleation such as g-tubulin. 20 Pericentrin adopts an extended conformation and is organized radially with its C terminus associated to the centriole wall and its N terminus extending toward the PCM periphery. 20 Microtubule nucleation is initiated by protein complexes containing g-tubulin and called gTuRC (g-Tubulin Ring Complexes).…”

“…20 Pericentrin adopts an extended conformation and is organized radially with its C terminus associated to the centriole wall and its N terminus extending toward the PCM periphery. 20 Microtubule nucleation is initiated by protein complexes containing g-tubulin and called gTuRC (g-Tubulin Ring Complexes). 22,23 The gTuRC is composed of gTuSC subunits (g-Tubulin Small Complex) formed by g-tubulin, GCP2 and GCP3 and assembled by additional proteins such as GCP4, GCP5 and GCP6.…”