Figure 1. Subdiffraction fluorescence microscopy view of the PCM architecture.

a) Schematic representations of the architectural elements of interphase centrosome. The three layers of organization—centrioles, PCM fibers and matrices—are represented separately to help visualization. The PCM is organized in two major layers of proteins 1) molecular fibers composed of the elongated coiled-coil proteins pericentrin/PLP and Cep152/Asl have their C-termini near the centriole wall and their N-termini extending towards the periphery 2) A PCM matrix composed of Cep215/Cnn, γ-tubulin and Cep192/Spd-2 molecules. See Fig. 2 for model with mitotic PCM. b) Positional mapping of pericentrin domains on interphase human centrosome. Top. Position of antibody/probe positions on human pericentrin with predicted coiled coil regions indicated. Bottom. Measurements of pericentrin diameter derived from 3DSIM micrographs of human cells stained with anti-pericentrin domain specific antibodies. The PACT domain is localized at the C-terminus with a diameter of ~ 200 nm consistent with the measurements electron micrographs. The N-termini is positioned at distance > 500 nm from the center of the centriole. c) 2D projections of averages of aligned 3D volumes of human centrosomes stained with antibodies against the C- and the N-termini regions of pericentrin. Modified from (37)