The centrosome duplication cycle in health and disease.

Centrioles function in the assembly of centrosomes and cilia. Structural and numerical centrosome aberrations have long been implicated in cancer, and more recent genetic evidence directly links centrosomal proteins to the etiology of ciliopathies, dwarfism and microcephaly. To better understand these disease connections, it will be important to elucidate the biogenesis of centrioles as well as the controls that govern centriole duplication during the cell cycle. Moreover, it remains to be fully understood how these organelles organize a variety of dynamic microtubule-based structures in response to different physiological conditions. In proliferating cells, centrosomes are crucial for the assembly of microtubule arrays, including mitotic spindles, whereas in quiescent cells centrioles function as basal bodies in the formation of ciliary axonemes. In this short review, we briefly introduce the key gene products required for centriole duplication. Then we discuss recent findings on the centriole duplication factor STIL that point to centrosome amplification as a potential root cause for primary microcephaly in humans. We also present recent data on the role of a disease-related centriole-associated protein complex, Cep164-TTBK2, in ciliogenesis.