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). Interacts specifically with keratin proteins including, KRT5, KRT6A, KRT8, KRT14, KRT16 and KRT18 (PubMed:15731013). Interacts with KCTD17 (PubMed:25270598). Expressed at high levels in normal urothelial and breast epithelial cells. Also expressed in the smooth muscle and endothelial cells. Reduced expression seen in advanced bladder and breast carcinomas (at protein level). Ubiquitous. Expressed at highest levels in the heart, skeletal muscle, kidney, liver and testis. Ubiquitinated. Ubiquitination by the BCR(KCTD17) E3 ubiquitin ligase complex results in proteasomal degradation, and induces ciliogenesis. Belongs to the TCHP family.