Sialic acids decorate all mammalian cells and play numerous important roles in cell surface biology. They serve as receptors of pathogens like influenza virus, that recognize these common molecular features of host cells. But they also serve as determinants of self for immune cell functions, allowing the immune system to distinguish between self and non-self. … Read more
1. Popot, J.-L. (2010). Amphipols, nanodiscs, and fluorinated surfactants: three non-conventional approaches to studying membrane proteins in aqueous solutions. Annu. Rev. Biochem. 79, 737-775. 2. Popot, J.-L., et al. (2011). Amphipols from A to Z. Annu. Rev. Biophys. 40, 379–408. 3. Banères, J.-L., et al. (2011). New advances in production and functional folding of G … Read more
TACC proteins play a crucial but as yet poorly understood role in the spatiotemporal control of microtubule assembly, and specifically in mitotic spindle assembly. Alp7 is an S. pombe TACC that binds tightly to Alp14, thought to be a tip-tracking microtubule polymerase, and carries it into the nucleus at the onset of mitosis. Using in … Read more
Peroxisomes are a new addition to the secretory pathway and form the endpoint of a new ER exit route. Although membrane proteins and lipids are acquired from the ER, peroxisomes handle the import of matrix proteins from the cytosol themselves via a peroxisome-specific translocon. We provide a new framework for organelle biogenesis whereby different ER-derived … Read more
Mitogenic growth factor receptors such as the epidermal growth factor receptor (EGFR) are tyrosine kinase receptors that are activated by ligand binding. One critical mechanism allowing the control of signalling responses downstream of EGFR is limiting the duration of EGFR activation, a process termed downregulation. Downregulation of EGFR involves its trafficking from the cell surface … Read more
Macrophages are versatile cells present in most tissues and endowed with a variety of different functions, including in innate and adaptive immunity against pathogens. Macrophages are targets of HIV and implicated in HIV-1 pathogenesis. They are also long-lived reservoir of virus that appear resistant to drug treatments and to attacks from the immune system. Infected … Read more
Ira Mellman is Vice President of Research Oncology at Genentech. Ira is a cell biologist with a long standing interest in membrane traffic. His lab is reponsible for key observations leading to the initial discovery of endosomes, the mechanisms of epithelial cell polarity, and the cellular basis of dendritic cell function. Until 2007, Ira was … Read more
Mitochondria are essential organelles whose functional integrity depends on a defined lipid composition of its membranes. The accumulation of phospholipids within mitochondria depends on interorganellar lipid transport between the ER and mitochondria, intramitochondrial phospholipid trafficking events and on the synthesis of cardiolipin or phosphatidylethanolamine within the organelle. We examine the function of prohibitins in the … Read more
The mechanisms of trafficking through cellular organelles such as the Golgi complex are intensively studied, but many questions remain unanswered. Small G proteins and membrane curvature sensors are key regulators of these membrane trafficking pathways. Activation of Arf1 is required for formation and maintenance of the Golgi, through recruitment of lipid modifying enzymes, protein coats … Read more
Once viewed simply as a reservoir for carbon storage, lipids are no longer cast as bystanders in the drama of biological systems. The emerging field of lipidomics is driven by technology, most notably mass spectrometry, but also by complementary approaches for the detection and characterization of lipids and their biosynthetic enzymes in living cells. The … Read more