A protein complex that acts as a chaperone or scaffold for centriolar proteins during the maturation of the procentriole. Some of its members may become integrated into the growing centriole. Examples are the CPAP(CENPJ)-STIL complex, CEP192-PLK4 complex or CEP152-PLK4 complex in vertebrates. [ http://www.ncbi.nlm.nih.gov/pubmed/22020124 http://www.ncbi.nlm.nih.gov/pubmed/17576815 http://www.ncbi.nlm.nih.gov/pubmed/21059844 http://www.ncbi.nlm.nih.gov/pubmed/24997597 http://www.ncbi.nlm.nih.gov/pubmed/18207742 ]