On this page
Cells survive, proliferate, and differentiate by interpreting the signals from the environment and translating them into the right output. If signaling goes awry, even in a few cells, the whole organism is at risk. We focus on signaling by the RAF/MEK/ERK pathway, an evolutionarily conserved kinase module which relays signals through consecutive phosphorylation of proteins arranged in three tiers. Constitutive activation of the pathway is a key event in several human malignancies and developmental disorders. Thus, proteins in this pathway are attractive therapeutic targets.
Strikingly, the pathway increases in complexity with evolution - from one paralog in simple organisms to three RAF, two MEK and two ERK paralogs in vertebrates. We investigate the essential roles of RAF and MEK paralogs and have discovered that they are indispensable for pathway cross‐talk, with functional consequences for homeostasis at the molecular, cellular, and organismal level.
The lab continues to focus on deciphering signaling pathways in the context of the whole organism, using a blend of genetics, molecular biology, biochemistry and cell biology. Since the essential functions of RAF and MEK paralogs are based primarily on their ability to undergo protein‐protein interactions with components of other signaling pathways, we are currently using an array of proximity labeling techniques coupled with mass spectrometry to understand the spatiotemporal context in which these complexes operate. To investigate the functional consequences of pathway perturbation, we rely mainly on primary cells and deploy single cell analysis of signaling pathways combined with single cell RNA‐seq to understand how RAF and MEK paralogs control cell fate decision.
Manuela is passionate about educating the next generation of scientists. She is the Director of the Vienna BioCenter PhD Program, a graduate school of the University of Vienna and Medical University of Vienna (link to the program website) and coordinates the FWF-funded PhD track “Signaling Mechanisms In Cellular Homeostasis”.
Hematopoietic stem cells (HSC) generate all cells in the blood, and are thus essential for our survival. HSC are rapidly activated when new blood is needed, but must go back to a dormant state lest the HSC compartment is exhausted. The fine balance between activation and dormancy is maintained by a negative feedback mechanism emanating from activated ERK and terminating ERK and AKT signaling.
The MEK paralog MEK1 dims signaling through the prosurvival PI3K/AKT pathway. Once modified by its substrate activated ERK, MEK1 binds to the lipid phosphatase PTEN and promotes its translocation to the plasma membrane. Here, PTEN breaks down the lipid second messenger PIP3, stopping AKT signaling. Thus, MEK1 balances signaling through two cascades that regulate cell proliferation and survival.
Activation of the RAF paralog RAF1 by growth factors and oncogenes generates distinct phosphorylated species which interact with the paralog BRAF, or with the cytoskeleton-based ROKα kinase. The BRAF complex is formed first and regulates ERK activation and proliferation, the ROKα complex regulates migration. RAF1 can be viewed as a moonlighting protein evolved to integrate distinct cell functions.
RAF1 ablation prevents the development and causes the regression of RAS-driven epidermal and lung tumors. In this system, RAS promotes complex formation between RAF1 and ROKα. RAF1 operates as an endogenous inhibitor of ROKα, which when unchecked induces exit from cell cycle and promotes keratinocyte differentiation.
RAF1 is required for RAS-driven lung and skin tumorigenesis. However in hepatocellular carcinoma (HCC) RAF1 puts the breaks on the proliferation of malignant hepatocytes, the actual tumor cells; therefore, and unexpectedly, RAF1 is a negative regulator of HCC. On the other hand, RAF1 is required in inflammatory cells of the tumor stroma to create an environment which stimulates HCC growth
29 March 2022
FEBS Journal Editor profile Manuela Baccarini
In this special interview series, the FEBS Journal profiles members of its editorial board: Read about Manuela's research, perspectives on the journal and future directions in her field.
Link: https://febs.onlinelibrary.wiley.com/share/TKQT7FK6FVRGMQIQCG5M?target=10.1111/febs.16423
17 February 2022
Interview: The social network of our cells
The group of Manuela Baccarini is investigating the way our cells communicate with each other. In this interview with "Rudolphina" by the University of Vienna, she talks about the 'signaling highway' in our bodies and about the way high throughput technologies revolutionised modern molecular cell biology research.
Link: https://rudolphina.univie.ac.at/cancer-research-when-communication-between-our-cells-fails
An ERK-Dependent Feedback Mechanism Prevents Hematopoietic Stem Cell Exhaustion.
Baumgartner, Christian; Toifl, Stefanie; Farlik, Matthias; Halbritter, Florian; Scheicher, Ruth; Fischer, Irmgard; Sexl, Veronika; Bock, Christoph; Baccarini, Manuela
MEK1 Is Required for PTEN Membrane Recruitment, AKT Regulation, and the Maintenance of Peripheral Tolerance.
Zmajkovicova, Katarina,Jesenberger, Veronika, Catalanotti,Federica, Baumgartner, Christian, Reyes, Gloria und Manuela Baccarini
A cell-autonomous tumour suppressor role of RAF1 in hepatocarcinogenesis.
Jeric, Ines; Maurer, Gabriele; Cavallo, Anna Lina; Raguz, Josipa; Desideri, Enrico; Tarkowski, Bartosz; Parrini, Matthias; Fischer, Irmgard; Zatloukal, Kurt; Baccarini, Manuela
Project title: “MEK1 complexes regulating the timing and strength of ERK and AKT signals" (P 26874)
Project title: “Role of MEK1 signaling in the regulation of hematopoiesis and leukemogenesis" (P 26303)
Project title: “Rolle der Raf Kinasen in Angiogenesis"
Project title: “The multi-scale dynamics of signal transduction: dissecting the MAPK pathway”
Manuela Baccarini co-ordinates the special Doctoral Program "Signaling Mechanisms in Cellular Homeostasis" reviewed and funded by the Austrian Science Fund FWF.
Identifying and exploiting cell-state dependent metabolic programs
Chromatin as a gatekeeper of chromosome replication
Mind matters. VBC mental health awareness
The multiple facets of Hop1 during meiotic prophase
Chromosomes as Mechanical Objects: from E.coli to Meiosis to Mammalian cells
Convergent evolution of CO2-fixing liquid-liquid phase separation
Viral envelope engineering for cell type specific delivery
New ways of leading: inclusive leadership and revising academic hierarchies
How an opportunistic human pathogen colonizes surfaces - From pathogen behavior to new drugs
Title to be announced
Decoding Molecular Plasticity in the Dark Proteome of the Nuclear Pore Complex
Probing the 3D genome architectural basis of neurodevelopment and aging in vivo
How to tango with four - the evolution of meiotic chromosome segregation after genome duplication
Multidimensional approach to decoding the mysteries of animal development
Membrane remodeling proteins at the junction between prokaryotes and eukaryotes
Connecting mitotic chromosomes to dynamic microtubules - insight from biochemical reconstitution
Neurodiversity in academia: strengths and challenges of neurodivergence
Gene expression dynamics during the awakening of the zygotic genome
When all is lost? Measuring historical signals
Suckers and segments of the octopus arm
Using the house mouse radiation to study the rapid evolution of genes and genetic processes
CRISPR jumps ahead: mechanistic insights into CRISPR-associated transposons
Title to be announced
Enigmatic evolutionary origin and multipotency of the neural crest cells - major drivers of vertebrate evolution
Visualising mitotic chromosomes and nuclear dynamics by correlative light and electron microscopy
Bacterial cell envelope homeostasis at the (post)transcriptional level
Polyploidy and rediploidisation in stressful times
Prdm9 control of meiotic synapsis of homologs in intersubspecific hybrids
RNA virus from museum specimens
Programmed DNA double-strand breaks during meiosis: Mechanism and evolution
Title to be announced