This family consists of several roughex (RUX) proteins specific to Drosophila species. Roughex can influence the intracellular distribution of cyclin A and is therefore defined as a distinct and specialised cell cycle inhibitor for cyclin A-dependent kinase activity [1]. Rux is though to regulate the metaphase to anaphase transition during development [2].

1: Roughex mediates G(1) arrest through a physical association with cyclin A. Avedisov SN, Krasnoselskaya I, Mortin M, Thomas BJ; Mol Cell Biol 2000;20:8220-8229. PMID:11027291

2: The cyclin-dependent kinase inhibitor Roughex is involved in mitotic exit in Drosophila. Foley E, Sprenger F; Curr Biol 2001;11:151-160. PMID:11231149