Overly Long Centrioles and Defective Cell Division upon Excess of the SAS-4-Related Protein CPAP

Abstract

Summary The centrosome is the principal microtubule organizing center (MTOC) of animal cells [1]. Accurate centrosome duplication is fundamental for genome integrity and entails the formation of one procentriole next to each existing centriole, once per cell cycle. The procentriole then elongates to eventually reach the same size as that of the centriole. The mechanisms that govern elongation of the centriolar cylinder and their potential relevance for cell division are not known. Here, we show that the SAS-4-related protein CPAP [2] is required for centrosome duplication in cycling human cells. Furthermore, we demonstrate that CPAP overexpression results in the formation of abnormal long centrioles. This also promotes formation of more than one procentriole in the vicinity of such overly long centrioles, eventually resulting in the presence of supernumerary MTOCs. This in turn leads to multipolar spindle assembly and cytokinesis defects. Overall, our findings suggest that centriole length must be carefully regulated to restrict procentriole number and thus ensure accurate cell division.

CPAP promotes timely cilium disassembly to maintain neural progenitor pool

“…In analyzing regions of CPAP‐ or CC5‐electroporated tissues, we found CPAP to partially rescue certain aspects of Seckel phenotype. This partial rescue could be due to CPAP overexpression itself (Kohlmaier et al , 2009; Tang et al , 2009). However, the rescue effect was more prominent in CC5‐transfected Seckel organoids as similarly observed with our NPCs experiments (Fig 4G).…”

Quantitative analysis of human centrosome architecture by targeted proteomics and fluorescence imaging

“…Although this observation may appear surprising, considering that Sas‐6 is a key structural component of the centriolar cartwheel (Gonczy, 2012; Hirono, 2014), it supports the view that recruitment of Sas‐6 to nascent centrioles is extensively controlled by posttranslational mechanisms (Dzhindzhev et al , 2014; Keller et al , 2014; Ohta et al , 2014; Arquint et al , 2015; Kratz et al , 2015). Similarly, although CPAP and CP110 have both been implicated in controlling the length of centrioles (Kohlmaier et al , 2009; Schmidt et al , 2009; Tang et al , 2009), their abundance in different cell lines shows no correlation, arguing that their functions at centrioles do not simply reflect protein concentration. Finally, we note that most centrosomal proteins were least abundant in the KE37 T‐lymphoblastoid line, which is commonly used for centrosome purification (Gosti‐Testu et al , 1986; Andersen et al , 2003).…”

“…The protein CPAP gets recruited to promote the assembly of microtubules onto the cartwheel (Tang et al , 2011a; Cottee et al , 2013; Sharma et al , 2016), and this step is likely assisted by Cep135 (the human homolog of Chlamydomonas Bld10) (Hirono, 2014). CPAP also cooperates with additional proteins, including CP110, in determining the length of nascent centrioles (Kohlmaier et al , 2009; Schmidt et al , 2009; Tang et al , 2009; Comartin et al , 2013; Lin et al , 2013; Sharma et al , 2016). Finally, centriole maturation is completed by the acquisition of subdistal and distal appendages (Paintrand et al , 1992; Tateishi et al , 2013).…”

Tankyrase 1 regulates centrosome function by controlling CPAP stability

“…Centrosomal P4.1-associated protein (CPAP), a human SAS4-related protein, was found to be required for centrosome function in human cells [6,7]. Depletion of CPAP in human cells prevented centrosome duplication, whereas overexpression of CPAP led to aberrant centriole elongation, supernumerary centrioles and spindle multipolarity [8][9][10][11]. A crucial role for CPAP and centriole maturation in humans is evidenced by its mutation in autosomal recessive primary microcephaly (MCPH) [12][13][14].…”