The Caenorhabditis elegans Centrosomal Protein SPD-2 Is Required for both Pericentriolar Material Recruitment and Centriole Duplication

Abstract

Taken together, our results suggest that SPD-2 may link PCM recruitment and centriole duplication in C. elegans. SPD-2 shares homology with a human centrosome protein, suggesting that this key component of the C. elegans centrosome is evolutionarily conserved.

Centrosomal protein of 192 kDa (Cep192) promotes centrosome-driven spindle assembly by engaging in organelle-specific Aurora A activation

“…Indeed, we found Cep192/oligomerization-mediated AurA activation to be critical for the function of MTOCs, both natural (centrosomes) and artificial (αAurA-coated beads). Parenthetically, the AurA-Cep192 function, reported here, is independent of centriole duplication/assembly (3,5,6), because exogenous, sperm nuclei-derived centrioles did not duplicate under the experimental conditions used (metaphase-arrested extract) (1, 2) and remained intact through the experiment (Fig. 3 A and D).…”

“…These observations suggest that the function of αAurA beads as MTOCs is a product of αAurA/dimerization-mediated AurA activation occurring on the bead surface. (3)(4)(5)(6), suggested that a common, Cep192-driven process underlies the development of MTOC activity by both centrosomes and αAurA beads. To explore this notion, we isolated a Xenopus laevis Cep192 cDNA encoding a 2,638 amino acid (aa), 289-kDa protein and raised Cep192-specific N-and C-terminally directed antibodies (αCep192-N and αCep192-C, respectively) ( Fig.…”

“…Protein recruitment during both centrosome duplication and maturation is controlled by centrosomal protein of 192 kDa (Cep192)/spindle defective 2 (Spd-2), a protein that operates by an unknown mechanism (3)(4)(5)(6). Among the proteins that localize to centrosomes in a Cep192-dependent manner is aurora A (AurA) (4,6), a serine/threonine kinase involved in mitotic entry, centrosome maturation, bipolar spindle assembly, and cell polarity (7,8).…”

The Centrosome and Its Duplication Cycle

“…The coiled-coil protein SPD-2 (spindle defective 2) was required to recruit the ZYG-1 protein kinase that, in turn, recruits the spindle assembly abnormal proteins SAS-6 and SAS-5 as a prerequisite for procentriole assembly and, finally, SAS-4, required for the addition of centriolar microtubules ( Kirkham et al 2003;Leidel and Gonczy 2003;Dammermann et al 2004;Delattre et al 2004Delattre et al , 2006Kemp et al 2004;Pelletier et al 2004Pelletier et al , 2006Leidel et al 2005). The functional homologs of these five proteins are highly conserved (Fig.…”

RNA interference rescue by bacterial artificial chromosome transgenesis in mammalian tissue culture cells

“…To test whether BAC-GFP tagging can be combined with cross-species RNAi rescue and thereby allow functional expression of the tagged protein in the absence of the endogenous protein, we inserted a GFP tag at the C terminus of the mouse homologue of the C. elegans SPD2 protein (39). Consistent with the localization pattern of SPD2 in C. elegans and its role in spindle assembly in the early embryo (39,40), the human homologue of SPD2 (hSPD2) also localizes to the centrosome (41).…”