Assistant Professor of Oncological Sciences
Adjunct Assistant Professor in Biomedical Engineering
B.S. Pennsylvania State University
Ph.D. University of California, San Diego
Michelle Mendoza's Lab Page
Michelle Mendoza's PubMed Literature Search
Molecular Biology Program
cell motility, cancer, signaling, ERK-MAPK
We are interested in the signaling of cell migration; how signals are delivered with spatiotemporal precision to control cytoskeletal dynamics and influence cell migration and cancer dissemination. Questions addressed in the lab include: how do signaling pathways integrate actin and adhesion dynamics for productive forward motion – how does pathway activation during oncogenesis enable invasive plasticity – and in lung cancer, what are the mechanisms of ERK activation and signaling that drive invasive progression? We approach these and other biological problems with a combination of biochemical and quantitative imaging techniques, using human cell lines, tumor tissue, and mouse models.
Cell movement involves cycles of leading edge protrusion and adhesion to the extracellular substrate, followed by de-adhesion and contraction of the cell body and rear. Actin assembles against the plasma membrane, generating pushing force that induces protrusions. Nascent adhesions assemble at the cell edge for traction force and undergo regulated disassembly versus maturation to balance forward motion and mechanical tension. Signaling pathways impinge on the intrinsic cytoskeleton cycles to control the proficiency of movement. The RAS®RAF®MEK®ERK signaling pathway is a key regulator of cell growth, proliferation, survival, differentiation, and also motility. It is also one of the most commonly activated pathways in solid tumors. We aim to understand ERK’s control of cell movement in normal cells, and the consequences of ERK misregulation in cancer dissemination.
Adhesion dynamics and integration with actin
We have established that ERK acts on the actin assembly machinery to directly promote rapid and sustained edge protrusion during cell movement. ERK phosphorylates the WAVE Regulatory Complex, which promotes WAVE’s interaction with, recruitment, and activation of the Arp2/3 actin nucleator at the cell edge. This increases actin assembly rates, which generates the pushing force needed to move the membrane forward. Drew Elliott and Keith Carney are investigating how ERK also controls nascent adhesions at the cell edge. Efforts are underway to identify and characterize the key substrates involved in adhesion turnover.
ERK and cancer invasion
When cancers spread throughout the body, tumor cells navigate altered local tumor microenvironments and foreign structures. The tumor cells adapt to invade by different motility modes that involve distinct cytoskeleton structures. Becca Goldstein is characterizing the tumor extracellular matrix composition and 3D arrangement. Jared Bergman is investigating novel ERK-mediated signaling inputs into the cytoskeleton machinery needed that facilitate movement through these variable environments.
Oncogenic RAS®RAF®MEK®ERK signaling is essential for lung adenocarcinoma initiation, maintenance, progression into invasive, metastatic disease. While common RAS and RAF mutations activate ERK, additional events are needed to bypass feedback loops and allow hyperactivation. Kelley Ingram, Shiela Samson, and Ran Lu are working to understand these additional ERK-activating events in lung cancer. They are also investigating the distinct roles of the ERK-regulated kinases p90 RSKs in lung cancer cell motility and in vivo progression.
- Michelle C. Mendoza*, Marco Vilela*, Jesus E. Juarez, John Blenis, and Gaudenz Danuser. ERK Reinforces Actin Polymerization to Power Persistent Edge Protrusion during Motility. Science Signaling 8(377):ra47 (2015).
- E. Emrah Er, Michelle C. Mendoza, Ashley M. Mackey, Lucia E. Rameh, and John Blenis. AKT Facilitates EGFR Trafficking and Degradation by Phosphorylating and Activating PIKfyve. Science Signaling 6(279):ra34 (2013). PMC4041878.
- Michelle C. Mendoza. Phosphoregulation of the WAVE Regulatory Complex and Signal Integration. Seminars in Cell and Developmental Biology 24(4):272-9 (2013). PMC3637877.
- Wenjuan Zhang, Michelle C. Mendoza, Xiaolei Pei, Didem Ilter, Sarah J. Mahoney, Yingmei Zhang, Dalong Ma, John Blenis, and Ying Wang. Down-regulation of CMTM8 Induces Epithelial-to-Mesenchymal-like Changes via c-MET/Extracellular Signal-Regulated Kinase (ERK) signaling. Journal of Biological Chemistry 287:11850-8 (2012). PMC3320933.
- Michelle C. Mendoza, Sebastien Besson, and Gaudenz Danuser. Quantitative Fluorescent Speckle Microscopy (QFSM) to Measure Actin Dynamics. Current Protocols in Cytometry 62:2.18.1-2.18.25 (2012). PMC3688286.
- Michelle C. Mendoza, E. Emrah Er*, Wenjuan Zhang*, Bryan A. Baliff, Hunter L. Elliott, Gaudenz Danuser, and John Blenis. ERK-MAPK Drives Lamellipodia Protrusion by Activating the WAVE2 Regulatory Complex. Molecular Cell 41:661-71 (2011). PMC3078620.
- Michelle C. Mendoza, E. Emrah Er, and John Blenis. The Ras-ERK and PI3K-mTOR Pathways: Cross-talk and Compensation. Trends in Biomedical Sciences 36:320-8 (2011). PMC3112285.