RB1 and ciliopathy: Our discovery of a novel severe human ciliopathy-related phenotype attributed to mutations in a kinetochore protein, supports recent evidence for a dual role for ciliary proteins in spindle orientation and ciliogenesis.19 CENP-F was first characterised in cancer cell lines as a component of the outer kinetochore and as a binding partner of the retinoblastoma (Rb) protein.33–35 CENP -F is dynamically expressed throughout the cell cycle.