Rose Johnstone

Rose Mamelak Johnstone FRSC (14 May 1928 – 3 July 2009) was a Canadian biochemist who is known for her discovery of exosomes, the cellular structures that transport proteins, lipids and RNA. She was the first woman to hold the Gilman Cheney Chair in Biochemistry and the first and only woman chair of the Department of Biochemistry in McGill University's Faculty of Medicine (1980-1990).

Johnstone was a pioneer for women in science and an advocate for gender equality. She is a Fellow of the Royal Society of Canada.

Early life Rose Johnstone (née Mamelak) was the second of four siblings born to Jacob Mamelak and Esther Rotholz, a Jewish family who emigrated from Poland to Montreal, Canada in 1936. Rose's mother encouraged her to apply for a scholarship, which allowed Rose to attend high school despite her family's poverty. She worked as a nurses' aide at the Montreal Neurological Institute during the summers and planned to pursue a career as a technical assistant.

Johnstone discovered exosomes through her work with red blood cells and iron uptake. While studying how iron enters maturing red blood cells, she discovered that only precursor reticulocytes could bind to iron. Her research showed that an iron-binding protein was absent from the surface of mature red blood cells and identified a new vesicle structure that allowed the iron-binding proteins to leave reticulocytes, enabling the maturation of red blood cells. She named this structure the "exosome." In this work she revealed a new pathway through which cells secrete exosomes. Exosomes play a role in cell communication in the immune system, the brain, and the heart.

Following her death, her son Michael, a cardiologist, established the Rose Mamelak Johnstone Research Bursary to support women researchers in McGill's Department of Biochemistry.

Awards

Fellow, National Cancer Institute of Canada (1954–58) Moyse Travelling Scholarship, Faculty of Science, McGill University (1954) Queen Elizabeth II Jubilee Silver Medal (1978) Fellow, Royal Society of Canada (1987) CSMB Jeanne Manery Fisher Memorial Lecture, Canadian Society for Molecular Biosciences (1991)