Autophagy researchers

Takahiko Akematsu

Email: taka@yorku.ca

Research focus

The study of programmed nuclear death and its relation to autophagy and apoptosis during sexual reproduction in Tetrahymena thermophila.

Model system

Tetrahymena thermophila (a unicellular ciliate protozoan).

Education and career

2010, PhD in Division of Life Science, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan; advisor: Dr. Hiroshi Endoh. 2010–2011, JSPS Research Fellow, Department of Biology, York University, Toronto, Canada; 2011–present, Banting Postdoctoral Fellow, Department of Biology, York University, Toronto, Canada; advisor: Dr. Ronald E. Pearlman.

Why do you study autophagy?

Tetrahymena thermophila has a spatially segregated germline micronucleus and somatic macronucleus in a single cytoplasm. The alteration of generations of Tetrahymena is performed between the two kinds of nuclei without fusion or disintegration of the cytoplasm, which is a novel type of sexual reproduction called “conjugation.” During conjugation, both progeny micro- and macronuclei commonly develop from the zygotic micronucleus, while the parental macronucleus is selectively eliminated from the cytoplasm by autophagy (see Akematsu et al., 2010, Autophagy). This process is called programmed nuclear death (PND).

Unlike the case of homeostatic autophagy such as starvation-induced autophagy, PND is required to finish the life span of the parental soma and ensure genomic diversification for progeny nuclei. How does the autophagy system recognize only the parental macronucleus? What is the intracellular signaling activated to execute PND? These questions are the starting point for our research. Understanding the mechanisms of autophagy that relate to the progression of PND and its regulation are crucial to addressing questions regarding the unique life cycle of Tetrahymena and will provide insights into important general questions involving autophagy.

What do you think is a key question in the autophagy field?

In any type of autophagy, how cells recognize the necessity for autophagy and then activate the downstream signaling is a key question. Indeed, whether a common mechanism is involved in the regulation across all eukaryotes is key and important.

What do you hope to achieve in your scientific career?

I have been using ciliated protozoa as a model biological system since I was an undergraduate student in Japan. My work with this system has brought me many invaluable scientific and personal opportunities such as to live and work abroad as a postdoctoral fellow, to meet exceptional scientists at international conferences, and to have a broad outlook of science and of life. Studying this unique system of the life cycle in ciliates, I hope that I can make novel contributions to studies on an important biological process. I hope that my research findings will lead to novel and important contributions throughout my career and allow me additional opportunities to explore science and life that, as a youth in Japan, I never dreamed would be possible.

Personal comments

I very much enjoy my current life in Toronto with a wonderful supervisor and colleagues in a strong, research-intensive environment. I can do without long, cold winters, but for the most part, Toronto is comfortable for outdoor activities. I have just started playing tennis and maybe I will learn to ski and skate to help survive winters. Since the city is very diverse with many groups and cultures represented, a variety of international restaurants are available. My present favorite is Italian.

Issidora Papassideri

Email: ipapasid@biol.uoa.gr

Research focus

The role of autophagy and apoptosis in insect development. Senescence and death signaling in erythrocytes.

Model system

Diptera (i.e., Drosophila melanogaster), Lepidoptera (i.e., Bombyx mori), erythrocytes.

Education and career

1979, biology degree, Faculty of Biology, National and Kapodistrian University of Athens (NKUA). 1986, PhD in cell biology, Faculty of Biology, NKUA; advisor: L. Margaritis. 1985–1986, postdoctoral research associate, EMBO Lab, Germany, Heidelberg; advisor: K. Leonard. 1986–1991, research associate, Faculty of Biology, NKUA. 1992–1999, lecturer, Faculty of Biology, NKUA. 1993, visiting fellow, Génétique Moléculaire Humaine CNRS, Médecine Grange Blance, Lyon. 1995, visiting fellow, Institut Pasteur de Lyon. 1999–2006, assistant professor, NKUA. 2007–present, associate professor, Department of Cell Biology and Biophysics, Faculty of Biology, NKUA. 2010–present, director of MSc “Educational Biology” and director of “Student Training Programme” Faculty of Biology, NKUA.

Why do you study autophagy?

My interest in autophagy derived from my initial study of apoptosis in insect oogenesis and in particular of the death mechanisms behind the nurse cells’ elimination in follicles of specific developmental stages. As it became apparent that programmed cell death also includes other forms, apart from apoptosis, I decided to focus on the study of autophagy in various insects, mostly of economic significance (such as Ceratitis capitata, Dacus oleae, etc., which, by feeding on plants in the field, cause considerable damage to crops), in order to clarify whether or not these two cell death mechanisms act synergistically in insect development.

What do you think is a key question in the autophagy field?

One of the most important questions regarding autophagy is the identification of the signaling key points that regulate whether autophagy will act as a protective cellular mechanism or as part of the programmed cell death machinery.

What is the funding situation now at your institution?

The economic crisis in Greece affects strongly the national research funding. Therefore, currently, only ECU funds can provide the financial support we need in order to continue our research projects.

Is teaching a substantial part of your current position?

My affiliation as a professor of cell and developmental biology at the University of Athens gives me the ability to spend a significant amount of my time teaching graduate and postgraduate students. I teach cell biology and developmental biology in undergraduate and postgraduate courses and I truly think that the interaction with my students benefits my research work in various ways, since a teacher has to study constantly in order to speak concisely and stay updated on the progress of her/his science. Most importantly, the discussions I often have with my students are always fruitful and broaden my perspectives, the way only pure minds can do. Conclusively, I think that my teaching obligations and my research activities complete each other and enhance my performance in both fields.

Personal comments

I like to spend my free time making long trips to places rich in cultural monuments and to areas of natural beauty. So far, some of the places I have visited include Machu Picchu in Peru, the pyramids of Mexico, the temple of Angkor Wat in Cambodia, the Great Wall of China, the pyramids of Giza in Egypt, Antarctica, Patagonia, the North Cape of Norway, the Nazca Lines (also in Peru), Lake Titikaka, the Silk Road, and the Gobi, Taklamakan, Atacama and Sahara Deserts. The status of the traveler gives me the opportunity to escape from my daily routine and enjoy new experiences. I also find great pleasure in literature. My favorite authors are Gabriel García Márquez, Umberto Eco and Jorge Luis Borges.

Laura Santambrogio

Email: laura.santambrogio@einstein.yu.edu

Research focus

Antigen processing and presentation, and immunosenescence.

Model system

Human and mouse dendritic cells and macrophages.

Education and career

1987, MD, University of Perugia, Perugia, Italy. 1993, PhD in immunology, University of Padua, Padua, Italy; advisor: Prof. G. Jeanette Thorbecke (New York University School of Medicine, NY, USA). 1994–1998, postdoctoral fellow, Harvard Medical School; advisor: Dr. Martin Dorf. 1999–2003, instructor, Dana-Farber Cancer Institute, Boston, MA, USA; advisor: Dr. Jack Strominger. 2003–present, professor of pathology, immunology and microbiology, Albert Einstein College of Medicine, Bronx, NY, USA.

Why do you study autophagy?

We are very interested in understanding how cells clear oxidatively damaged and aggregated proteins, a process in which autophagy plays an important role. Specifically, we found that a hallmark of senescent myeloid cell precursors and bona fide conventional dendritic cells is the presence of an extensively glycated, carbonylated and lipoxidated proteome. The increasingly carbonylated proteome and endosomal accumulation of these aggregates interferes with mouse and human dendritic cell immune function. The biological damage imparted by protein oxidation is 2-fold: first, oxidized proteins can be altered in their structure, or biological function, or can be targeted for early degradation; and second, oxidized misfolded proteins tend to aggregate into progressively larger micro- or macro-deposits that interfere with cellular functions. Mapping the oxidative moieties on the cellular proteome and analyzing the molecular pathways involved in their catabolism is an important step toward ameliorating innate and adaptive immune responses in immunosenescence.

A second line of research we are very interested in is the characterization of endosomal microautophagy in dendritic cells and macrophages. Our group, in collaboration with the laboratory of Ana Maria Cuervo, was the first to describe endosomal microautophagy in mammalian cells. This less-known form of autophagy occurs during late endosome multivesicular body biogenesis and relies on the ESCRT-I and -III systems for formation of the vesicles in which the cytosolic cargo is internalized. Protein cargo selection is mediated by the chaperone HSPA8/HSC70 and requires the cationic domain of HSPA8 for electrostatic interactions with the endosomal membrane.

What do you think is a key question in the autophagy field?

The relationship between oxidative stress and autophagy.

Personal comments

In my early career, my children (two sons and one daughter) were the priority. Now, science has a major role in my daily activities. I am an avid reader and enjoy spending time browsing the numerous exhibitions at the MOMA and Metropolitan museums in New York City.

Shweta Saran

Email: ssaran@mail.jnu.ac.in or shweta_saran@hotmail.com

Research focus

Cell differentiation in Dictyostelium discoideum and understanding the process of autophagy using this model system.

Model system

Dictyostelium discoideum.

Education and career

1991, PhD from Banaras Hindu University, Varanasi, Uttar Pradesh, India; advisor: Dr. M.S. Kanungo (deceased). 1991–1993, postdoctoral fellow, Indian Institute of Science, Bangalore, Karnataka; advisor: Dr. Vidyanand Nanjundiah. 1993, visiting scientist, National Institute of Biology, Okazaki, Japan; advisor: Dr. Ikuo Takeuchi. 1994–2001, scientist, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India. 2001–2003, research assistant, Wellcome Trust, University of Dundee, UK; advisor: Dr. Pauline Schaap. 2003–2005, reader, University of Delhi, India. 2005–present, associate professor, School of Life Sciences, Jawaharlal Nehru University.

Why do you study autophagy?

Dictyostelium discoideum follows a vacuolar form of developmental cell death, which is caspase independent. In this organism, one of the two terminally differentiated cell types, namely the stalk cells, dies by a specific programmed cell death that has the characteristics of autophagic cell death. Since it occupies a unique phylogenetic position, findings in Dictyostelium could throw some light on the evolution of this process. We are trying to study the regulatory pathways that could control autophagy in this organism. Understanding the details of the mechanism from this organism may help us manipulate autophagy, which could help fight disease and promote health.

What do you think is a key question with regard to autophagy?

To understand the fine line that drives autophagy toward cell survival or toward cell death.

What do you hope to achieve in your career?

I want to enjoy science and contribute an original piece of work. As a teacher, I hope to deliver my best and motivate my students to contribute their best to society.

If you could choose a different career what would it be?

A career in academics (science) was always my first choice, but when my daughter was born (during the initial years of my PhD) I discovered a flair for dress designing. If I had to choose another career I would definitely choose this.

Is teaching a substantial part of your current position?

Yes, teaching is a substantial part of my current position. I teach a core paper (2 credits) to master’s students on animal developmental biology and an optional paper (3 credits) in developmental biology to MPhil/PhD students. I also teach courses in cell signaling (MPhil/PhD students) and present a few lectures in other courses. Finally, I teach developmental biology to master’s students from other universities located in Delhi.

Personal comments

Outside the lab, my world revolves around my daughter, who is a filmmaker, and my husband who is a geneticist. I love to relax in my daughter’s new home. I like to listen to music (Indian semi-classical vocals and old film songs) and read books related to history (Indian, British, Middle East and China).