The Tumor Suppressor CYLD Interacts with TRIP and Regulates Negatively Nuclear Factor κB Activation by Tumor Necrosis Factor

Abstract

Cylindromas are benign adnexal skin tumors caused by germline mutations in the CYLD gene. In most cases the second wild-type allele is lost in tumor tissue, suggesting that CYLD functions as tumor suppressor. CYLD is a protein of 956 amino acids harboring a functional deubiquitinating domain at the COOH-terminal end. To shed more light on the function of CYLD, we have performed a yeast two hybrid screen using an HaCaT cDNA library that identified the RING finger protein TRIP (TRAF-interacting protein) as interactor with full-length CYLD. Mapping of the interacting domains revealed that the central domain of CYLD binds to the COOH-terminal end of TRIP. Far Western analysis and coimmunoprecipitations in mammalian cells confirmed that full-length CYLD binds to the COOH-terminal domain of TRIP. Because TRIP is an inhibitor of nuclear factor (NF)-κB activation by tumor necrosis factor (TNF), the effect of CYLD on NF-κB activation was investigated in HeLa cells. The results established that CYLD down-regulates NF-κB activation by TNF-α. The inhibition by CYLD depends on the presence of the central domain interacting with TRIP and its deubiquitinating activity. These findings indicate that cylindromas arise through constitutive NF-κB activation leading to hyperproliferation and tumor growth.

Mutations in the NF-κB signaling pathway: implications for human disease

“…Cylindromas are considered as originating from a transformation event specifically affecting the folliculo-sebaceous unit that produces hair and its associated glands. The mutated gene, CYLD, encodes a tumor suppressor protein (Bignell et al, 2000) that can negatively regulate NF-kB activation (Brummelkamp et al, 2003;Kovalenko et al, 2003;Regamey et al, 2003;Trompouki et al, 2003). CYLD is a member of the deubiquitinase family of enzymes that can specifically hydrolyse poly-ubiquitin chains of the 'K63' type.…”

NF-κB-related genetic diseases

“…68,69 Besides binding to NEMO, CYLD has also been shown to interact with TRAF2 and TRIP. [68][69][70] In another study, CYLD has been recovered following a whole-scale search aimed at identifying members of the deubiquitinase family controling NF-kB activation by TNF-a. 71 Upon overexpression, CYLD has been shown to negatively regulate NF-kB activation induced by TNF-a, IL-1-b or CD40 and its deubiquitinase activity is required for this function.…”

An inactivating CYLD mutation promotes skin tumor progression by conferring enhanced proliferative, survival and angiogenic properties to epidermal cancer cells

“…Cyld encodes a 956-amino acid enzyme (CYLD) that is ubiquitously expressed and contains a deubiquitinating domain at the C-terminus, which removes lysine 63 linked polyubiquitin chains from distinct members of the nuclear factor (NF)-kB pathway (Brummelkamp et al, 2003;Kovalenko et al, 2003;Regamey et al, 2003;Trompouki et al, 2003). CYLD negatively regulates NF-kB activation, and mutations that inactivate the carboxyl-terminal deubiquitinating domain of CYLD deregulate the NF-kB activity, underlying the development of skin appendage tumors in humans (Brummelkamp et al, 2003;Kovalenko et al, 2003;Trompouki et al, 2003).…”