Tag Archives: multiple molecular forms

Multiple molecular forms of adaptor protein Ruk/CIN85 specifically associate with different subcellular compartments in human breast adenocarcinoma MCF-7 cells

B. O. Vynnytska-Myronovska1, Ya. P. Bobak1, G. V. Pasichnyk2,
N. I. Igumentseva1, A. A. Samoylenko2, L. B. Drobot2

1Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv;
2Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: drobot@biochem.kiev.ua

Ruk/CIN85 is a receptor-proximal ‘signalling’ adaptor that possesses three SH3 domains, Pro- and Ser-rich regions and C-terminal coiled-coil domain. It employs distinct domains and motifs to act as a transducer platform in intracellular signalling. Based on cDNA analysis, various isoforms of Ruk/CIN85 with different combination of protein-protein interaction domains as well as additional Ruk/CIN85 forms that are the products of post-translational modifications have been demonstrated. Nevertheless, there is no precise information regarding both the subcellular distribution and the role of Ruk/CIN85 multiple molecular forms in cellular responses. Using MCF-7 human breast adenocarcinoma cells and cell fractionation technique, specific association of Ruk/CIN85 molecular forms with different subcellular compartments was demonstrated. Induction of apoptosis of MCF-7 cells by doxorubicin treatment or by serum deprivation resulted in the system changes of Ruk/CIN85 molecular forms intracellular localization as well as their ratio. The data obtained provide a new insight into potential physiological significance of Ruk/CIN85 molecular forms in the regulation of various cellular functions.