Speaker: Professor Pablo Saez, Cell Communication and Migration Laboratory, UKE, Hamburg

Title: Decision-making during cell migration: cytoskeleton and organelles
Time: 24 September 2026, 10:00-11:00
Location: Lauren 1, Medisiina D

Talk Abstract:

Cell migration is central to organ development, tissue regeneration, metastasis, and immunity. To navigate the complexity of the tissue, moving cells use cell polarity, which is set by the orientation of organelles and cytoskeleton. Migrating cells often encountering obstacles and junctions, where their path branches into alternative directions, such as cells moving on top or within blood vessels. However, how cells decide a new direction, when the decision is unbiased, remains largely unknown. Similarly, it is poorly understood howmigrating cells coordinate organelle distribution and function during directional migration. Here, we use in vitro and in vivo live-cell imaging using different levels of complexity, advanced image analysis to analyze the response of migrating cells when facing symmetric junctions, and extreme branching when cells simultaneously face several bifurcations. We found that actin and membrane dynamics play a key role to choose a new direction in both cases i) when cells face a single symmetric junction (Y-shaped with equal angles, Ron et al. 2024), and ii) when cells exhibit high levels of branching because they face several junctions at the same time (Liu et al.). In addition, we found that the organelle dynamics, crosstalk, and chemical identity is spatially segregated in polarized cells, and their function is key to maintain the direction of migration.

About the speaker:

Pablo J. Sáez is a cell biologist from Chile where he did most of his training until the PhD working in cell communication and inflammation in the lab at the Juan Sáez lab (Catholic University). Then, he did a short transition in the same university, in the lab of Marcelo Farías working in organelles, in particular in obesity-induced ER stress. Then, he came to Europe as a postdoc to work in leukocyte migration and organelle polarity in the lab of Ana-María Lennon at the Institut Curie in Paris. From there he move to the lab of Matthieu Piel at IPGG-Curie (in the group of Pablo Vargas) to continue his work in leukocyte migration and microfluidics. In 2020 he started his own group as a Full Professor at the UKE in Hamburg, and since 2022 he leads a HFSP grant team (in collaboration with Yamuna Krishnan and Nir Gov) dedicated to understand directional decision-making. He also has a keen interest in promoting diversity, mentoring, scientific communication, and SciArt, with participations as an eLife ambassador, and member of scientific advisory board of Focal Plane.