CCBIO Seminar – Staffan Strömblad
We are happy to invite to a CCBIO Seminar with speaker Staffan Strömblad from the Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
Speaker: Staffan Strömblad, Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
Title: Novel cell-matrix adhesion structures
In the first part of the talk the nano-scale organization of integrins within focal adhesions will be described. Integrins fluctuate between active and inactive conformations, yet whether the activity state influences the spatial organization of integrins within focal adhesions has remained unclear. We have addressed this question and also asked whether integrin activity may be regulated independently for each integrin molecule, or through locally coordinated mechanisms. We first revealed a spatial hierarchy of integrin organization, with integrin molecules arranged in nanoclusters, which align to form linear sub-structures that in turn build focal adhesions. Remarkably, within focal adhesions, active and inactive β1 integrins segregated into distinct nanoclusters, with active integrin nanoclusters being more organized.
In the second part of the talk a novel type of adhesions will be described. Adhesion to the extracellular matrix (ECM) persists during mitosis in most cell types. However, while classical adhesion complexes, such as focal adhesions, do and must disassemble to enable mitotic rounding, the mechanisms of residual mitotic cell-ECM adhesion remain undefined. We have identified ‘reticular adhesions’, a novel class of adhesion complex that is mediated by integrin αvβ5, formed during interphase, and preserved at cell-ECM attachment sites throughout cell division. Mass spectrometry defined their unique composition, enriched in phosphatidylinositol-4,5-bisphosphate (PI-4,5-P2)-binding proteins, but lacking virtually all consensus adhesome components. Indeed, reticular adhesions are promoted by PI-4,5-P2, and form independently of talin and F-actin. The distinct characteristics of reticular adhesions provide a solution to the problem of maintaining cell-ECM attachment during mitotic rounding and division.
Chairperson: Donald Gullberg, CCBIO
Time: Thursday September 27th 2018 at 14.30
Place: Auditorium 4, BB building, Bergen
Open for all. All are also welcome to the pizza get-together following the seminar!
CCBIO has a monthly research seminar where invited guests and international or national speakers focus on current research topics and updates.
The CCBIO Seminar series fulfills several aims.
- Firstly, it conveys relevant biomarker research to the local scientific community and students and younger researchers in particular, providing the ground for future recruitment.
- Secondly, it is part of two formal courses, BMED 380 on the master level, and together with the CCBIO Annual Symposium, forms CCBIO 902, a PhD level course.
- Last, but not least, the CCBIO seminars with their subsequent open pizza get-together are an important arena for informal interaction between international researchers, CCBIO PIs and other CCBIO staff as well as interested researchers and students in general.
All interested researchers, students and others are welcome!