Tumor suppressor which has the ability to inhibit cell growth and be pro-apoptotic during cell stress. Inhibits cell growth in bladder and prostate cancer cells by a down-regulation of HSPB1 by inhibiting its phosphorylation. May act as a 'capping' or 'branching' protein for keratin filaments in the cell periphery. May regulate K8/K18 filament and desmosome organization mainly at the apical or peripheral regions of simple epithelial cells (PubMed:15731013, PubMed:18931701). Is a negative regulator of ciliogenesis (PubMed:25270598).