Academic Profile

Academic Profile

Asst Prof Alexander Ludwig

Assistant Professor, School of Biological Sciences

Asst Prof Alexander Ludwig

2013 - 2018: Senior Research Fellow. School of Biological Sciences, NTU, Singapore.
2008 - 2013: Career Development Fellow (postdoc) at Medical Research Council – Laboratory of Molecular Biology, Cambridge UK
2003 - 2008: PhD; Department of Biochemistry and the Neuroscience Centre Zurich (ZNZ), University of Zurich, Switzerland
Research Interests
Cell polarity is a fundamental property of almost all cell types, and its loss or deregulation frequently leads to human diseases such as cancer. My lab is interested in the mechanisms that establish and maintain apico-basal polarity of epithelial cells. We are particularly interested in understanding how membrane compartmentalization controls cell polarity, on the cellular, molecular, and structural level.

One line of research focuses on the apical junctional complex (AJC), an intricate membrane compartment that is located at the boundary between the apical and the lateral membrane. The AJC plays many important roles in epithelial cells; it connects adjacent cells into a tight monolayer, it controls the passage of molecules across epithelial tissues, and it serves as a diffusion barrier that physically separates apical and baso-lateral membrane components. In addition, the AJC serves as a signaling and trafficking platform for epithelial morphogenesis and plasticity, and it is linked to the cortical cytoskeleton to regulate tissue mechanics. We are interested in the nanometer-scale organisation of the AJC and in identifying and functionally characterising novel regulators of this intriguing multi-functional membrane domain.

Another line of research tackles the regulation of the protein network that sets up cell polarity in the first place. Here we focus our efforts on the polarity proteins Par, Scribble and Crumbs, which are central to the establishment and maintenance of cell polarity. We are interested in the molecular and spatial organization of the polarity network, and in understanding how this network functions in time and space.

My lab combines cell biological, biochemical, and structural approaches with high-resolution imaging including light and electron microscopy and correlative imaging.
Current Projects
  • Molecular Mechanisms of Membrane Compartmentalisation in Cell Polarity
  • Phase plate imaging and cryo-EM analysis of macromolecular assemblies
  • What is the tight junction protein ZO3 doing at the base of the primary cilium?
Selected Publications
  • Benedict Tan, Siti Maryam J.M. Yatim, Suat Peng, Jayantha Gunaratne, Walter Hunziker, Alexander Ludwig. (2020). The Mammalian Crumbs Complex Defines a Distinct Polarity Domain Apical of Epithelial Tight Junctions. Current Biology, (30), 1-14.
  • Tie, HC, Ludwig, A, Sandin, S, Lu, L. (2018). The spatial separation of processing and transport functions to the interior and periphery of the Golgi stack. eLIFE, 30(7), doi: 10.7554/eLife.41301.
  • Ludwig A, Nguyen TH, Leong D, Ravi LI, Huan TB, Sandin S, Sugrue RJ. (2017). Caveolae provide a specialized membrane environment for respiratory syncytial virus assembly. Journal of Cell Science, 130(6), 1037-1050.
  • Ludwig A, Nichols BJ and Sandin S. (2016). Architecture of the caveolar coat complex. Journal of Cell Science, 129(16), 3077-83.
  • Ludwig A, Howard G, Mendoza-Topaz C, Deerinck T, Mackey M, Sandin S, Ellisman MH, Nichols BJ. (2013). Molecular Composition and Ultrastructure of the Caveolar Coat Complex. PLos Biology, 11(8), e1001640.

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