Germline-specific role for unconventional components of the γ-tubulin complex inCaenorhabditis elegans

Abstract

ABSTRACTThe γ-tubulin complex (γTuC) is a widely conserved microtubule nucleator, but some of its components GCP4–6. Here, we identified two γTuC-associated proteins inC. elegans, namely GTAP−1 and −2, for which apparent orthologs were detected only in the genusCaenorhabditis. Their centrosomal localization was interdependent. In earlyC. elegansembryos, whereas the conserved γTuC component MZT-1/MOZART1 was essential for the localization of centrosomal γ-tubulin, depletion of GTAP-1 and/or −2 caused up to 50% reduction of centrosomal γ-tubulin and precocious disassembly of spindle poles during mitotic telophase. In the adult germline, GTAP-1 and GTP-2 contributed to the efficient recruitment of γTuC to the plasma membrane. Depletion of GTAP-1, but not GTAP-2, severely disrupted both the microtubule array and the honeycomb-like structure in the adult germline.We propose that GTAP-1 and −2 are unconventional components of γTuC that contribute to the organization of both centrosomal and non-centrosomal microtubules by targeting the γTuC to specific subcellular sites in a tissue-specific manner.SUMMARY STATEMENTHaruta et al. show that GTAP-1 and −2, two unconventional components of the γ-tubulin complex (γTuC) inC. elegans, contribute to targeting the γTuC to embryonic centrosomes and germ-cell membrane in adults.