The Drosophila Pericentrin-like-protein (PLP) cooperates with Cnn to maintain the integrity of the outer PCM

Abstract

Centrosomes comprise a pair of centrioles surrounded by a matrix of pericentriolar material (PCM). In vertebrate cells, Pericentrin plays an important part in mitotic PCM assembly, but the Drosophila Pericentrin-like protein (PLP) appears to have a more minor role in mitotic fly cells. Here we investigate the function of PLP during the rapid mitotic cycles of the early Drosophila embryo. Unexpectedly, we find that PLP is specifically enriched in the outer-most regions of the PCM, where it largely co-localizes with the PCM scaffold protein Cnn. In the absence of PLP the outer PCM appears to be structurally weakened, and it rapidly disperses along the centrosomal microtubules (MTs). As a result, centrosomal MTs are subtly disorganized in embryos lacking PLP, although mitosis is largely unperturbed and these embryos develop and hatch at near-normal rates. Y2H analysis reveals that PLP can potentially form multiple interactions with itself and with the PCM recruiting proteins Asl, Spd-2 and Cnn. A deletion analysis suggests that PLP participates in a complex network of interactions that ultimately help to strengthen the PCM.

Drosophila pericentrin‐like protein promotes the formation of primordial germ cells

“…During cell‐cycle progression, centrosomes duplicate and become fully separated by prophase along with an accompanying increase in microtubule nucleation (Tanenbaum & Medema, ). Previous work indicates PLP serves as a centrosome scaffold protein and also contributes to centrosome separation in the soma region of syncytial embryos (Lerit et al, ; Richens et al, ). A plausible hypothesis, therefore, is that defects in centrosome separation may contribute to the aberrant PB protrusion in plp mutants.…”

“…To mechanistically address how loss of plp disrupts microtubule assembly, we examined the distribution of Cnn at PB centrosomes in control versus plp GLC embryos. Cnn is a core component of a PCM scaffold required for centrosome and microtubule organization (Conduit, Brunk, et al, ; Conduit, Feng, et al, ; Lerit et al, ; Megraw, Li, Kao, & Kaufman, ; Richens et al, ). In control PBs, Cnn radiates from interphase centrosomes (Figure c, WT interphase), similar to the Cnn flares previously described in the soma (Megraw et al, ).…”

“…The microtubule-nucleating activity of centrosomes is instructed through the pericentriolar material (PCM), a composite of numerous proteins that surrounds the central pair of centrioles (Nigg & Raff, 2009). We recently demonstrated a direct interaction between the PCM components Cnn and Pericentrin (Pcnt)-like-protein (PLP) supports the formation of a centrosome scaffold required to organize the PCM structure (Lerit et al, 2015;Richens et al, 2015). Loss of either cnn or plp results in similar embryonic defects: disorganized PCM and microtubules, centrosome spacing defects, aberrant spindle formation, and embryonic lethality (Lerit et al, 2015;Megraw, Kilaru, Turner, & Kaufman, 2002).…”

Structural Basis for Mitotic Centrosome Assembly in Flies

“…R1141 is required for CM2 to interact with two other proteins, PLP and Centrocortin (Kao and Megraw, 2009, Lerit et al., 2015). Substituting R1141 for His abolishes these interactions, but this substitution had only a minor effect on Cnn localization and scaffold assembly compared to the CM2 deletion (Figure 4C)—although the Cnn flares at the periphery of the PCM were destabilized due to the failure to interact with PLP, as shown previously (Lerit et al., 2015, Richens et al., 2015). Thus, the previously described interactions between CM2 and PLP or Centrocortin are not sufficient to explain the role of CM2 in centrosomal targeting or scaffold assembly.…”

Does Unc–GFP uncover ciliary structures in the rhabdomeric eye of Drosophila?

“…2D). Given that PLP is more concentrated around the mother centriole in somatic Drosophila tissues (Fu and Glover, 2012;Richens et al, 2015), we asked whether the Unc signal was restricted to the mother centriole in the developing eye. Thus, we look at the distribution of centrobin, a good marker for daughter centrioles in Drosophila (Januschke et al, 2013).…”