It is with great sadness, that we are informing Prof. Irena Kąkol passed away on September 29th, 2021. Prof. I. Kąkol was associated with the Nencki Institute for almost half a century, starting work in 1951, when the Institute, after WWII, was based in Łódź. It was just after her graduation from the Faculty of Mathematics and Natural Sciences of the University of Łódź, with a master degree in philosophy in the field of chemistry. She became a member of the Department of Biochemistry, headed by Prof. Włodzimierz Niemierko, actively involved in research on muscle proteins, in particular myosin; she remained faithful to this research topic throughout her entire research career. In 1953, she moved with the team of Prof. Niemierko to the Institute’s Warsaw location. She worked there until 1995, but was actively involved in research until the turn of the century. After that, she was also a frequent guest of the Institute, participating, for example, in the celebrations of the Institute's Centenary in November 2018.

Her many years of research focused on understanding the mechanisms of the effects of myosin regulatory light chain phosphorylation on interaction of myosin and actin filaments during contraction of skeletal and cardiac muscles. She obtained a doctorate in natural sciences in 1961, on the basis of the dissertation "Qualitative and quantitative changes in the composition of actomyosin phosphorus compounds during its action on ATP”, under the supervision of prof. Włodzimierz Niemierko. After her doctorate, she completed a research internship at the Hans Weber laboratory at Max-Planck-Institut für Physiologie in Heidelberg, where she was involved in research on nucleotide exchange during actin polymerization/depolymerization. In 1972, she received a postdoctoral degree in natural sciences in the field of biology, and she became full professor in 1992. In 1974, the Laboratory of Molecular Basis of Muscle Contraction was established, which she headed until 1993, that is, until reaching her retirement age.

She authored 36 articles published mainly in English-language journals, a Polish monograph on the structure and function of myosin, and a translation from German of the textbook on dynamic biochemistry by Eberhard Hofmann. She presented her achievements at many international scientific conferences, and cooperated fruitfully with researchers from many foreign centers, including the Center d 'Etudes de Saclay in Gif-sur-Yvette, the Institute of Molecular Biology of the Austrian Academy of Sciences in Salzburg, the Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences (RAN) in Pushchino, the Institute of Cytology RAN in Petersburg, Moscow State University and Kiev University.

In addition to her scientific work, Prof. I. Kąkol, for 35 years, was the head of the radiation laboratory, which was used very intensively during those years; it absorbed a lot of her attention. She was also active in the social field, for many years she was a member of the Polish Teachers' Union (ZNP), in which for over a decade she was the chairman of the Institute works council; she was also a member of the presidium of the board of the branch within the Polish Academy of Sciences. After retiring, she remained with the Institute union for a number of years, giving advice and assistance to her successors. As a trade unionist, she proved to be friendly and helpful to people, often defending them during disputes with the Institute authorities. She also looked after colleagues in her laboratory (she promoted six doctors), who could always count on her support, not only on the side of scientific topics.

For her scientific and organizational achievements, she was awarded several times, with state distinctions and decorations (including the Officer's Cross of the Order of Polonia Restituta and the Gold Badge of ZNP). Her research received, inter alia, Award of the Scientific Secretary of the Polish Academy of Sciences, and the Parnas Award of the Polish Biochemical Society for the best article in the field of biochemistry.

She reconciled her active involvement in the Institute and its community with the duties of a wife and mother of three children. She will be sorely missed as a great colleague, devoted to science and the Institute, and one of the last members of the Łódź "landing".

Prof. dr hab. Jolanta Rędowicz