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Roberto Weigert, Ph.D.

Roberto Weigert, Ph.D.

  • Center for Cancer Research
  • National Cancer Institute

RESEARCH SUMMARY

Dr. Weigert’s research focuses on the basic mechanisms that regulate trafficking events in mammalian tissues, with a particular emphasis on membrane remodeling. He has pioneered subcellular intravital microscopy to image these processes in live animals under physiological conditions, and to investigate their role during tumor progression, invasion, and metastasis. His work has highlighted the principles that control the temporal and spatial coordination in vivo among cell signaling, actin cytoskeleton, and cellular bioenergetics, and their relationship to modifications of the composition and biophysical properties of cellular membranes.

Areas of Expertise

1) membrane trafficking and remodeling, 2) intravital microscopy, 3) actin cytoskeleton, 4) bioenergetics, 5) exocytosis and endocytosis, 6) invasion and metastasis

Publications

Selected Recent Publications

Dynamic polyhedral actomyosin lattices remodel micron-scale curved membranes during exocytosis in live mice

Ebrahim S, Chen D, Weiss M, Malec L, Ng Y, Rebustini I, Krystofiak E, Hu L, Liu J, Masedunskas A, Hardeman E, Gunning P, Kachar B, Weigert R.
Nat Cell Biol. 21(8): 933-9, 2019. [ Journal Article ]

Intravital microscopy in mammalian multicellular organisms

Ebrahim S, Weigert R
Curr Opin Cell Biol. 59: 97-103, 2019. [ Journal Article ]

Concerted actions of distinct nonmuscle myosin II isoforms drive intracellular membrane remodeling in live animals.

Milberg O, Shitara A, Ebrahim S, Masedunskas A, Tora M, Tran DT, Chen Yi, Conti MA, Adelstein RS, Ten Hagen KG, Weigert R.
J Cell Biol. 216(7): 1925-36, 2017. [ Journal Article ]

Sinusoidal ephrin receptor EPHB4 controls hematopoietic progenitor cell mobilization from bone marrow

Kwak H, Salvucci O, Weigert R, Martinez-Torrecuadrada JL, Henkemeyer M, Poulos MG, Butler JM, Tosato G.
J Clin Invest. 126(12): 4554-68, 2016. [ Journal Article ]

In vivo tissue-wide synchronization of mitochondrial metabolic oscillations

Porat-Shliom N, Chen Y, Tora M, Shitara A, Masedunskas A, and Weigert R
Cell Reports. 2: 514-521, 2014. [ Journal Article ]

Job Vacancies

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Team

Predoctoral Visiting Fellow (Graduate Student)
Desu Chen
Research Fellow
Seham Ebrahim, Ph.D.
Postdoctoral Fellow (Visiting)
Nicolas Melis, Ph.D.
Postdoctoral Fellow (Visiting)
Yeap Ng, Ph.D.
Postdoctoral Fellow (Visiting)
Bhagawat Subramanian, Ph.D.
Postdoctoral Fellow (CRTA)
Weiye Wang, Ph.D.

Covers

Micrograph of a transgenic mouse line that expresses green fluorescent protein

Kinetics of milk lipid droplet transport, growth, and secretion revealed by intravital imaging: lipid droplet release is intermittently stimulated by oxytocin

Published Date

Description of the cover: The micrograph shows lipid droplets (red) accumulating at the apical surface of secretory cells (green) between oxytocin-induced contractions in a transgenic mouse line that expresses green fluorescent protein in the cytoplasm of most cells.

Abstract:  The lipid droplet (LD) fraction of milk has attracted special attention because it supplies preformed lipids for neonatal development, and the assembled LDs are secreted by a unique apocrine mechanism. Because many aspects of this key process remain uncharacterized, we developed a facile method for the intravital imaging of mammary cells in transgenic mice that express fluorescently tagged marker proteins. Using these techniques, we describe the first kinetic analysis of LD growth and secretion at peak lactation in real time. LD transit from basal to apical regions was slow (0–2 μm/min) and frequently intermittent. Droplets grew by the fusion of preexisting droplets, with no restriction on the size of fusogenic partners. Most droplet expansion took several hours and occurred in apical nucleation centers, either close to or in association with the apical surface. Droplets even continued to expand as they were emerging from the cell. Contrary to expectations, LDs attached to the apical plasma membrane but still associated with the cytoplasm were released after oxytocin-mediated contraction of the myoepithelium. Thus milk LD secretion is an intermittently regulated process. This novel procedure will have broad application for investigating trafficking events within the mammary epithelium in real time.

Citation