CYLD negatively regulates cell-cycle progression by inactivating HDAC6 and increasing the levels of acetylated tubulin

Abstract

CYLD is a tumour-suppressor gene that is mutated in a benign skin tumour syndrome called cylindromatosis. The CYLD gene product is a deubiquitinating enzyme that was shown to regulate cell proliferation, cell survival and inflammatory responses, mainly through inhibiting NF-jB signalling. Here we show that CYLD controls cell growth and division at the G 1 /S-phase as well as cytokinesis by associating with a-tubulin and microtubules through its CAP-Gly domains. Translocation of activated CYLD to the perinuclear region of the cell is achieved by an inhibitory interaction of CYLD with histone deacetylase-6 (HDAC6) leading to an increase in the levels of acetylated a-tubulin around the nucleus. This facilitates the interaction of CYLD with Bcl-3, leading to a significant delay in the G 1 -to-S-phase transition. Finally, CYLD also interacts with HDAC6 in the midbody where it regulates the rate of cytokinesis in a deubiquitinase-independent manner. Altogether these results identify a mechanism by which CYLD regulates cell proliferation at distinct cell-cycle phases.

GLI1-dependent transcriptional repression of CYLD in basal cell carcinoma

“…We have shown in previous studies that CYLD reduces proliferation and cyclin D1 expression by slowing the G1/S phase transition in keratinocytes and melanoma cells (Wickstrom et al, 2010). To investigate whether the cells with reduced CYLD expression were proliferating, we used the proliferation marker Ki-67 and cyclin D1.…”

“…Hh/GLI signaling has been shown to induce proliferation via activation of critical G1/S cell cycle genes, including D-type cyclins (Kenney and Rowitch, 2000;Regl et al, 2004). We recently demonstrated that CYLD reduces cell proliferation by decreasing the rate of cell division at the G1/S phase (Wickstrom et al, 2010). Here, we found that release of synchronized keratinocytes by addition of tetracycline caused a delay in G1 to S phase transition in CYLD-transfected cells, but not in mock-transfected cells (Figure 4d).…”

“…Quantitative real-time PCR was performed with specific primers for CYLD, Cyclin D1, GLI1 and Snail1 (Supplementary Table S2). The cell cycle analysis of primary keratinocytes post synchronisation was performed as described previously (Wickstrom et al, 2010). Lentiviral GLI1 or GLI2 short-hairpin RNA constructs were purchased from the Mission RNAi set (Sigma, St Louis, MO, USA) and murine BCC cells were stably transduced as described previously (Kasper et al, 2007).…”

Cellular defence or viral assist: the dilemma of HDAC6

“…Alternative splicing [161] 14-3-3z Lys 49 /Lys 120 Suppression of growth and survival signalling [162] (GRK2) [35,36], aurora A [37] and protein kinase C isoform z (PKCz) [38], are also found to phosphorylate and increase HDAC6 tubulin deacetylase activity at positions that remain undefined. Another example of enhanced HDAC6 activity by phosphorylation is provided by protein kinase CK2 (formerly casein kinase II), which phosphorylates HDAC6 at position 458 (Ser 458 ) to enhance the formation and clearance of aggresomes [39].…”

“…Phosphorylation of TPPP1 by Rho-associated coiled-coil kinase (ROCK) and cyclin-dependent kinase 1 (CDK1) impairs the interaction between TPPP1 and HDAC6, which, in turn, results in increased HDAC6 activity followed by a decrease in cell motility and an increase in cell proliferation, respectively [46,47]. Moreover, a broad spectrum of regulators, which directly interact with and inhibit HDAC6 tubulin deacetylase activity or aggresome formation ability, has been well documented, including paxillin [48], CYLD [49,50], dysferlin [51], Mdp3 [52], p62 [53] and RanBPM [54].…”