Mechanism of action of a WWTR1 (TAZ)-CAMTA1 fusion oncoprotein

MR Tanas, S Ma, FO Jadaan, CKY Ng, B Weigelt… - Oncogene, 2016 - nature.com
MR Tanas, S Ma, FO Jadaan, CKY Ng, B Weigelt, JS Reis-Filho, BP Rubin
Oncogene, 2016nature.com
The WWTR1 (protein is known as TAZ)-CAMTA1 (WC) fusion gene defines epithelioid
hemangioendothelioma, a malignant vascular cancer. TAZ (transcriptional coactivator with
PDZ binding motif) is a transcriptional coactivator and end effector of the Hippo tumor
suppressor pathway. It is inhibited by phosphorylation by the Hippo kinases LATS1 and
LATS2. Such phosphorylation causes cytoplasmic localization, 14-3-3 protein binding and
the phorphorylation of a terminal phosphodegron promotes ubiquitin-dependent …
Abstract
The WWTR1 (protein is known as TAZ)-CAMTA1 (WC) fusion gene defines epithelioid hemangioendothelioma, a malignant vascular cancer. TAZ (transcriptional coactivator with PDZ binding motif) is a transcriptional coactivator and end effector of the Hippo tumor suppressor pathway. It is inhibited by phosphorylation by the Hippo kinases LATS1 and LATS2. Such phosphorylation causes cytoplasmic localization, 14-3-3 protein binding and the phorphorylation of a terminal phosphodegron promotes ubiquitin-dependent degradation (the phosphorylation of the different motifs has several effects). CAMTA1 is a putative tumor suppressive transcription factor. Here we demonstrate that TAZ-CAMTA1 (TC) fusion results in its nuclear localization and constitutive activation. Consequently, cells expressing TC display a TAZ-like transcriptional program that causes resistance to anoikis and oncogenic transformation. Our findings elucidate the mechanistic basis of TC oncogenic properties, highlight that TC is an important model to understand how the Hippo pathway can be inhibited in cancer, and provide approaches for targeting this chimeric protein.
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