The centrosome, composed of a pair of centrioles (mother and daughter centrioles) and pericentriolar material, is mainly responsible for microtubule nucleation and anchorage in animal cells. The subdistal appendage (SDA) is a centriolar structure located at the subdistal region on the mother centriole, and it functions in microtubule anchorage. However, the molecular composition and detailed structure of SDA remain largely unknown. Here, we identified a-taxilin and r-taxilin as new SDA components, which form a complex via their coiled-coil domains and serve as a new subgroup during SDA hierarchical assembly. Their SDA localization is dependent on ODF2, and α-taxilin recruits CEP170 to the SDA. Functional analyses suggest that α-taxilin and γ-taxilin are responsible for centrosomal microtubule anchorage during interphase, as well as for proper spindle orientation during metaphase. Altogether, our results shed light on the molecular components and functional understanding of the SDA hierarchical assembly and microtubule organization.
