
Sandra Scharaw, PhD
Group Leader
Sandra has an educational background in Cell and Molecular Biology. During her PhD she studied secretory membrane machinery regulation of cells using imaging-based membrane transport assays. For her postdoctoral studies, Sandra translated her membrane biology knowledge to the tissue level. She focused her research on the organisation of secretory membrane organelles in adult tissue stem cells and developed approaches in 3D organoid culture systems to study membrane transport in stem cell-mediated tissue renewal.
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Scientific Career
| 2024 – Now | Research Group Leader at the MPI-CBG |
| 2016 – 2024 | Postdoctoral work, Karolinska Institute Stockholm, Sweden Department of Cell and Molecular Biology with Pekka Katajisto |
| 2011 – 2016 | PhD, EMBL Heidelberg, Germany Cell Biology and Biophysics Unit with Rainer Pepperkok |
| 2006 – 2011 | Diploma in Molecular Biology, University of Kassel, Germany with one year abroad study at Griffith University, Brisbane, Australia |
Awards
| 2019 | Swedish Society of Medical Research Postdoctoral Fellowship |
| 2017 | EMBO Long-Term Postdoctoral Fellowship (ALTF 155-2017) |
| 2017 | Christiane Nüsslein-Volhard Postdoctoral Fellowship |
| 2009 | DAAD-RISE North America Research Scholarship |
| 2006 | Hessen-Queensland Program Study Scholarship |

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David Grommisch, PhD
MSCA Postdoctoral Researcher
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PhD
Medical Science, Karolinska Institutet, Sweden – Group of Dr. Maria Genander
M.Sc.
Biomedicine, Karolinska Institutet, Sweden
B.Sc.
Molecular Biotechnology, Heidelberg University, Germany
How cells communicate and interact to form and maintain complex tissues fascinates me. In my PhD I focused on epithelial progenitor cell behaviour of the skin and oesophagus and how their cellular environment regulates cell fate decisions. I focused on in vivo lineage tracing, organoid models, and next generation sequencing techniques.
As a Postdoc I want to delve deeper into the cellular biology of intercellular communication by visualising cell-cell communication in intestinal organoids. I hope this helps me to understand how altered intercellular communication contributes to stem cell dysfunction with age.
Outside the lab I enjoy doing sports, cooking (& eating!), reading, and visiting and spending time with friends. I enjoy arts and music and wish I’d take more time to play guitar again. Maybe in later years I wish I’d worked more on investigating ageing while I play the guitar.

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Jun Yang, PhD
Postdoctoral Researcher
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PhD
Chemical and Biomolecular Engineering, University of Notre Dame, USA – Group of Dr. Pinar Zorlutuna
M.Sc.
Chemical and Biomolecular Engineering, Johns Hopkins University, USA
B.Sc.
Environmental Engineering, South China Normal University, China
I started my scientific journey in bioengineering, where I explored drug delivery and tissue engineering in cancer, and became fascinated by how the microenvironment shapes cell behaviors in health and disease. During my PhD, I focused on how the aging tumor microenvironment influences breast cancer progression, using engineered 3D models and extracellular vesicle analysis to study cell–matrix interactions and age-specific drug responses.
As a postdoc in Sandra’s group, I am excited to expand my work on cell–cell and cell–matrix communication, particularly in the context of stem cell and aging biology. I hope to integrate my background in bioengineering with the lab’s expertise in cell biology to better understand how aging alters tissue organization and stem cell functions.
Outside the lab, I share my free time with my cat Yuumi. We read, knit, watch movies and sports, listen to music and true crime podcasts while we play fetch and cuddle.

Musashi Koyama, PhD
Postdoctoral Researcher

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Helin Giris Timurtas, MsC
PhD candidate
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M.Sc.
Double-degree in International Master’s Program in Innovative Medicine,
Heidelberg University, Germany +
Uppsala Universitet, Sweden
B.Sc.
Molecular Biology and Genetics,
Izmir Institute of Technology, Izmir, Türkiye
During my bachelor’s studies, I rotated through different scientific hubs, where I exposed myself to a variety of techniques and perspectives to better understand biology from multiple angles. Soon after, although I majored in molecular biology, I became increasingly interested in cellular-level dynamics in health and disease. At the same time, I focused on learning diverse methods, including advanced imaging techniques, iPSC culture, and the production of lab-on-a-chip devices.
For my PhD, I want to specifically explore the subcellular and cellular dynamics of the intestinal crypt niche. By utilising advanced imaging methods, I aim to investigate the organisation of endomembrane organelles within the intestinal stem cell niche. Ultimately, I believe that uncovering the importance of endomembrane organelle organisation will deepen our understanding of the dynamics of ageing.
Outside the lab or the microscopy room, you will probably find me at the gym, where I enjoy lifting weights. Besides that, I like reading novels, watching movies, and spending time with family and friends.

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Joon Ho Lee, MsC
Technician
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M.Sc.
Chemistry, Yonsei University, Seoul, Korea
B.Sc.
Biochemistry, University of Wisconsin – Madison, USA
I started my scientific journey as a biochemistry undergraduate at University of Wisconsin – Madison. After enduring some heavy snowstorms in winters and enjoying my time next to Lake Mendota in summers, I graduated from Madison and started my master’s program in chemistry at Yonsei University in Seoul.
After completing my master’s degree, I relocated to Dresden in 2020 (bad year to travel, terrible year to move to a new country…oof). Despite the initial challenges, I have been enjoying my time living and working in Dresden and in Germany. Since I started to work in Dresden, I have mainly gained experience with organoids, African clawed frog (xenopus laevis), various mouse work to name a few.
Since I became a part of MPI-CBG, I am very happy to be working at Sandra Scharaw’s group as a TA and helping the group whenever possible!
Outside of the lab, I like to spend my time cooking something new, visiting restaurants and cafés, traveling in and out of Europe, and practicing clarinet (Squidward style).