Tag Archives: adaptor protein Ruk/CIN85

Department of Cell Signaling relay race of time: from studying the structure and function of individual proteins to analyzing protein–protein interaction networks

O. O. Hudkova, L. B. Drobot*

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine,
Department of Cell Signaling, Kyiv;
*e-mail: drobot@biochem.kiev.ua

Received: 30 September 2025; Revised: 08 October 2025;
Accepted: 30 October 2025; Available on-line: 2025

The review presents the history of establishment, key achievements, and development prospects of the Department of Cell Signaling at the Palladin Institute of Biochemistry of the NAS of Ukraine. As a structural unit of the institution, the Department was established in 2018 through the merger of two separate subdivisions: one of the oldest, the Department of Metabolic Regulation (founded in 1944), and the youngest, the Laboratory of Cell Signaling (founded in 2006). From its inception, the department’s primary research focus has been the study of the structure and functions of individual animal and microbial proteins. Significant contributions to the fundamental and applied achievements during that period were made by leaders of the Department, Dr.Sci., Professor Szörényi E.T., and Academician of NASU Huliy M.F., which were recognized with State Prizes of the USSR and the Ukrainian SSR (1953, 1978, 1988). Considerable attention has been given­ to transforming the department’s research direction to meet modern standards in molecular cell biology, a shift logically linked to the work of the unified unit under the leadership of Dr.Sci., Professor L.B. Drobot. This transformation involved not only the formal merger of two teams but also the integration of their scientific accomplishments and intellectual potential, combining traditional and innovative research approaches. The scientific paths of both subdivisions inevitably converged, necessitating joint investigations in response to contemporary challenges and societal demands. The department’s central focus became the elucidation of signaling mechanisms involved in the coordinated regulation of proliferation, differentiation, and apoptosis in normal and transformed cells with the participation of adaptor/scaffold protein Ruk/CIN85. Through the efforts of the department’s researchers, the pivotal role of Ruk/CIN85 in controlling the plasticity of tumor cells of various origins was convincingly demonstrated–particularly in the development of cancer stem cell traits, chemoresistance, tumor progression, and/or differentiation.

Extracellular vesicles produced by mouse breast adenocarcinoma 4T1 cells with up- or down-regulation of adaptor protein Ruk/CIN85 differentially modulate the biological properties of 4T1 WT cells

A. Yu. Zhyvolozhnyi1,2*, I. R. Horak1, D. S. Geraschenko1, M. O. Gomozkova3,
O. O. Hudkova1, S. J. Vainio2, A. A. Samoylenko2, L. B. Drobot1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland;
3Brigham Young University-Idaho, Rexburg, USA;
*e-mail: ppndl2@gmail.com

Received: 02 November 2021; Accepted: 12 November 2021

Extracellular vesicles (EVs) are secreted by most cell types under both physiological and pathological conditions and were proposed to be actively involved in intercellular communication. The mode of EVs action is dependent on their cargos composition. EVs  play an important role in tumor initiation, recurrence, metastasis and therapeutic resistance. EVs marker proteins Alix and Tsg101 and cortactin are the binding partners of adaptor protein Ruk/CIN85. The present study aims to analyze the regulatory effects of EVs produced by 4T1 cells with overexpression (RukUp) or down-regulation (RukDown) of adaptor protein Ruk/CIN85 on proliferation rate, migration and invasion activity of parental 4T1 WT cells. EVs from conditioned medium of 4T1 RukUp or RukDown cells were isolated by differential centrifugation followed by further purification using Exo-spin™ kit (Cell Guidance Systems). The number and size of EVs were characterized by NTA (Malvern Panalytical NanoSight NM300) instrument. The content of marker proteins and Ruk/CIN85 in isolated EVs was analyzed by Western-blotting. The viability, migration and invasion activity of 4T1 WT cells were studied using MTT-test, scratch-test and Boyden chamber assay, respectively. It was demonstrated for the first time that adaptor protein Ruk/CIN85 is a constitutive component of  EVs produced by 4T1 cells. It was also shown that EVs produced by 4T1 cells with different levels of Ruk/CIN85 expression are characterized by a specific profile of the content of its multiple molecular forms. It turned out that the ability of EVs to modulate the proliferative activity, motility and invasiveness of 4T1 WT cells was tightly correlated with the biological properties of 4T1 cells that produce EVs (highly aggressive 4T1 RukUp cells or weakly invasive 4T1 RukDown cells). Our data suggest that adaptor protein Ruk/CIN85 is not only a constitutive component of cargos composition of EVs produced by tumor cells but, depending on its content in EVs, plays an active role in the control of carcinogenesis.

Adaptor protein Ruk/CIN85 affects redox balance in breast cancer cells

I. R. Horak*, N. V. Latyshko, O. O. Hudkova, T. O. Kishko,
O. V. Khudiakova, D. S. Gerashchenko, T. D. Skaterna,
I. P. Krysiuk, S. G. Shandrenko, L. B. Drobot

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: iryna.horak@gmail.com

Received: 25 February 2020; Accepted: 15 May 2020

Excessive reactive oxygen species (ROS) production may lead to damage of cellular proteins, lipids and DNA, and cause cell death. Our previous findings demonstrated that increased level of adaptor protein Ruk/CIN85 contributes to breast cancer cells malignancy. The aim of this study was to investigate the role of Ruk/CIN85 in the maintaining of the redox balance in cancer cells. Mouse breast adenocarcinoma 4T1 cells with different levels of Ruk/CIN85 expression were used as a model in this study. Activities of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), aldehyde dehydrogenase (ALDH) and formaldehyde dehydrogenase (FALDH), as well as H2O2 and aldehydes content were measured using fluorometric assays. Gene expression correlations between Ruk/CIN85 and antioxidant enzymes in breast cancer samples were analyzed using ist.medisapiens transcriptomic database. It was demonstrated that Ruk/CIN85-overexpressing 4T1 cells were characterized by increased production of H2O2 and reduced activities of CAT, GPx and SOD. Overexpression of Ruk/CIN85 resulted in decreased content of aldehydes together with increased activity of ALDH, while in Ruk/CIN85-knocked down 4T1 cells, activities of ALDH and FALDH were decreased. The data of transcriptomic analysis revealed the correlations between SH3KBP1 expression and CAT, GPX4, ALDH1A1, ALDH1L1, ALDH2, GSR, SOD1 in human breast carcinomas samples. The obtained results indicate that adaptor protein Ruk/CIN85 affects redox balance in mouse breast adenocarcinoma 4T1 cells.

Transcriptional regulation of NOX genes expression in human breast adenocarcinoma MCF-7 cells is modulated by adaptor protein Ruk/CIN85

A. V. Bazalii, I. R. Horak, G. V. Pasichnyk, S. V. Komisarenko, L. B. Drobot

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: drobot@biochem.kiev.ua

NADPH oxidases are key components of redox-dependent signaling networks involved in the control of cancer cell proliferation, survival and invasion. The data have been accumulated that demonstrate specific expression patterns and levels of NADPH oxidase homologues (NOXs) and accessory genes in human cancer cell lines and primary tumors as well as modulation of these parameters by extracellular cues. Our previous studies revealed that ROS production by human colorectal adenocarcinoma HT-29 cells is positively correla­ted with adaptor protein Ruk/CIN85 expression while increased levels of Ruk/CIN85 in weakly invasive human breast adenocarcinoma MCF-7 cells contribute to their malignant phenotype through the constitutive activation of Src/Akt pathway. In this study, to investigate whether overexpression of Ruk/CIN85 in MCF-7 cells can influence transcriptional regulation of NOXs genes, the subclones of MCF-7 cells with different levels­ of Ruk/CIN85 were screened for NOX1, NOX2, NOX3, NOX4, NOX5, DUOX1 and DUOX2 as well as for regulatory subunit p22Phox mRNA contents by quantitative RT-PCR (qPCR). Systemic multidirectional changes in mRNA levels for NOX1, NOX2, NOX5, DUOX2 and p22Phox were revealed in Ruk/CIN85 overexpressing cells in comparison to control WT cells. Knocking down of Ruk/CIN85 using technology of RNA-interference resulted in the reversion of these changes. Further studies are necessary to elucidate, by which molecular mechanisms Ruk/CIN85 could affect transcriptional regulation of NOXs genes.