Long Noncoding RNA NIHCOLE Promotes Ligation Efficiency of DNA Double-Strand Breaks in Hepatocellular Carcinoma

Juan P Unfried, Mikel Marín-Baquero, Ángel Rivera-Calzada, Nerea Razquin, Eva M Martín-Cuevas, Sara de Bragança, Clara Aicart-Ramos, Christopher McCoy, Laura Prats-Mari, Raquel Arribas-Bosacoma, Linda Lee, Stefano Caruso, Jessica Zucman-Rossi, Bruno Sangro, Gareth Williams, Fernando Moreno-Herrero, Oscar Llorca, Susan P Lees-Miller, Puri Fortes

Abstract: Long noncoding RNAs (lncRNA) are emerging as key players in cancer as parts of poorly understood molecular mechanisms. Here, we investigated lncRNAs that play a role in hepatocellular carcinoma (HCC) and identified NIHCOLE, a novel lncRNA induced in HCC with oncogenic potential and a role in the ligation efficiency of DNA double-stranded breaks (DSB). NIHCOLE expression was associated with poor prognosis and survival of HCC patients. Depletion of NIHCOLE from HCC cells led to impaired proliferation and increased apoptosis. NIHCOLE deficiency led to accumulation of DNA damage due to a specific decrease in the activity of the nonhomologous end-joining (NHEJ) pathway of DSB repair. DNA damage induction in NIHCOLE-depleted cells further decreased HCC cell growth. NIHCOLE was associated with DSB markers and recruited several molecules of the Ku70/Ku80 heterodimer. Further, NIHCOLE putative structural domains supported stable multimeric complexes formed by several NHEJ factors including Ku70/80, APLF, XRCC4, and DNA ligase IV. NHEJ reconstitution assays showed that NIHCOLE promoted the ligation efficiency of blunt-ended DSBs. Collectively, these data show that NIHCOLE serves as a scaffold and facilitator of NHEJ machinery and confers an advantage to HCC cells, which could be exploited as a targetable vulnerability. SIGNIFICANCE: This study characterizes the role of lncRNA NIHCOLE in DNA repair and cellular fitness in HCC, thus implicating it as a therapeutic target.See related commentary by Barcena-Varela and Lujambio, p. 4899.

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Structure of the TELO2-TTI1-TTI2 complex and its function in TOR recruitment to the R2TP chaperone

Mohinder Pal, Hugo Muñoz-Hernandez, Dennis Bjorklund, Lihong Zhou, Gianluca Degliesposti, J Mark Skehel, Emma L Hesketh, Rebecca F Thompson, Laurence H Pearl, Oscar Llorca and  Chrisostomos Prodromou

Abstract: The R2TP (RUVBL1-RUVBL2-RPAP3-PIH1D1) complex, in collaboration with heat shock protein 90 (HSP90), functions as a chaperone for the assembly and stability of protein complexes, including RNA polymerases, small nuclear ribonucleoprotein particles (snRNPs), and phosphatidylinositol 3-kinase (PI3K)-like kinases (PIKKs) such as TOR and SMG1. PIKK stabilization depends on an additional complex of TELO2, TTI1, and TTI2 (TTT), whose structure and function are poorly understood. The cryoelectron microscopy (cryo-EM) structure of the human R2TP-TTT complex, together with biochemical experiments, reveals the mechanism of TOR recruitment to the R2TP-TTT chaperone. The HEAT-repeat TTT complex binds the kinase domain of TOR, without blocking its activity, and delivers TOR to the R2TP chaperone. In addition, TTT regulates the R2TP chaperone by inhibiting RUVBL1-RUVBL2 ATPase activity and by modulating the conformation and interactions of the PIH1D1 and RPAP3 components of R2TP. Taken together, our results show how TTT couples the recruitment of TOR to R2TP with the regulation of this chaperone system.

LINK a la publicación.

A molecular view of DNA flexibility

No te pierdas la revisión del grupo de nuestro coordinador Fernando Moreno-Herrero sobre los conocimientos que se pueden obtener de las propiedades mecánicas del DNA con experimentos de molécula única y simulaciones de dinámica molecular.

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Type VII secretion systems: structure, functions and transport models

Angel Rivera-Calzada, Nikolaos Famelis, Oscar Llorca & Sebastian Geibel

Abstract: Type VII secretion systems (T7SSs) have a key role in the secretion of effector proteins in non-pathogenic mycobacteria and pathogenic mycobacteria such as Mycobacterium tuberculosis, the main causative agent of tuberculosis. Tuberculosis-causing mycobacteria, still accounting for 1.4 million deaths annually, rely on paralogous T7SSs to survive in the host and efficiently evade its immune response. Although it is still unknown how effector proteins of T7SSs cross the outer membrane of the diderm mycobacterial cell envelope, recent advances in the structural characterization of these secretion systems have revealed the intricate network of interactions of conserved components in the plasma membrane. This structural information, added to recent advances in the molecular biology and regulation of mycobacterial T7SSs as well as progress in our understanding of their secreted effector proteins, is shedding light on the inner working of the T7SS machinery. In this Review, we highlight the implications of these studies and the derived transport models, which provide new scenarios for targeting the deathly human pathogen M. tuberculosis.

LINK a la publicación.

Buenas noticias: NanoBioCancer continuará en 2021

Teniendo en cuenta los buenos resultados científicos del consorcio, correspondientes al primer periodo de ejecución de la ayuda, se ha propuesto la continuación del proyecto NanoBioCancer-CM (Ref. Y2018/BIO-4747) para la tercera anualidad. ¡Enhorabuena por el trabajo a tod@s!