Rootletin, also known as ciliary rootlet coiled-coil protein (CROCC) is a protein in humans that is encoded by the CROCC gene. Rootletin is a component of the ciliary rootlet and, together with CEP68 and CEP250, is required for centrosome cohesion.

Rootletin is an important protein in the ciliary rootlet, particularly for the structure and is considered important protein in mitosis as a centrosome linker.

This protein forms part of the ciliary rootlet structure. It also contributes to the centrosome cohesion before mitosis. Expression of rootletin leads to the formation of fibrous protein.

This protein is part of the structure of a ciliary rootlet. This cytoskeletal-like structure starts from the basal body at one end of the cilium and extends towards the nucleus. Its molecular structure consists of a globular head domain and a tail domain made up of coiled-coil structures.

A large coiled-coil protein, C-Nap1, is a docking site for the fibrous tether to proximal ends of centrioles which Rootletin physically interacts with. Furthermore, Rootletin is phosphorylated by Nek2 kinase.