In this week’s PNAS online, researchers at Dennis Selkoe’s lab at Harvard University, and Huilin Li’s lab at Brookhaven National Laboratory, Upton, New York, report the 3D structure of purified γ-secretase. Minji Kim, Alice Lu, and Rudy Tanzi, Massachusetts General Hospital, first brought us news of this structure as part of their coverage of the Keystone Symposia Meeting held last February. As that summary revealed, first author Vlado Lazarov and colleagues used the electron microscope to determine that γ-secretase exists as a particle 120 Angstroms in length with an internal cylindrical chamber about 20-40 Angstroms long. The structure has ~20 Angstrom openings at the top and bottom, which could conceivably allow exit of cleavage products to the extracellular and intracellular milieus. A supporting movie, showing the pores, is available for download at the PNAS website.—Tom Fagan
- Lazarov VK, Fraering PC, Ye W, Wolfe MS, Selkoe DJ, Li H. Electron microscopic structure of purified, active gamma-secretase reveals an aqueous intramembrane chamber and two pores. Proc Natl Acad Sci U S A. 2006 May 2;103(18):6889-94. PubMed.