Dlg, Scribble and Lgl in cell polarity, cell proliferation and cancer

Dig (Discs large), Scrib (Scribble) and LgI (Lethal giant larvae) are evolutionarily conserved components of a common genetic pathway that link the seemingly disparate functions of cell polarity and cell proliferation in epithelial cells. dig, scrib and /g/have been identified as tumour suppressor genes in Drosophila, mutations of which cause similar phenotypes, involving disruption of cell polarity and neoplastic overgrowth of tissues. The molecular mechanisms by which Dig, Scrib and LgI proteins regulate cell proliferation are not clear, but there is some evidence that epithelial polarisation is required for this regulation. Dig, Scrib and LgI are highly conserved between human and Drosophila, and we discuss evidence that these proteins also play a role in cancer progression in humans. BioEssays25:542-553,2003. (C) 2003 Wiley Periodicals, Inc.