Tel:	617-525-5511
	Fax:	617-525-5252
	E-Mail:	mwolfe@rics.bwh.harvard.edu
	Location:	Center for Neurologic Diseases Brigham and Women's Hospital and Harvard Medical School 77 Avenue Louis Pasteur, H.I.M. 754 Boston, MA 02115
	Homepage:	-

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The Wolfe lab studies intramembrane proteases that play critical roles both in normal biology and in human disease. The last place in the cell to expect hydrolysis is within the hydrophobic environment of the lipid bilayer. Nevertheless, a number of multi-pass membrane proteins appear to carry out this seemingly paradoxical process (see Wolfe and Selkoe, Science, 2002). Such proteases cut within the transmembrane region of their respective substrates, and consistent with this observation, these proteases contain putative catalytic residues located within transmembrane domains.

The specific focus of the lab has been on the chemistry and biology of γ -secretase. This protease is critical to the pathogenesis of Alzheimer's disease and to cell differentiation during embryonic development (see Esler and Wolfe, Science, 2001). Small organic inhibitors were developed and used as tools to characterize and identify γ-secretase. Findings from the lab implicate a multi-pass protein called presenilin as the catalytic component of a larger γ-secretase complex. Missense mutations in presenilin cause hereditary Alzheimer's disease, and these mutations specifically affect γ-secretase activity.

The lab has recently found that presenilin and a presenilin-associated protein called nicastrin copurify with γ-secretase activity from an immobilized inhibitor, evidence that nicastrin is also a member of the protease complex (Esler et al. Proc Natl Acad Sci USA , 2002). Moreover, a γ-secretase substrate also copurified, suggesting an initial substrate docking site on the protease complex distinct from the active site (see the figure). Helical peptides designed to interact with this docking site can potently inhibit γ-secretase activity both in cell-free and cell-based assays (Das et al., J Am Chem Soc, 2003). Along with presenilin and nicastrin, two other membrane proteins, aph-1 and pen-2, are also essential components of the complex (Kimberly et al. Proc Natl Acad Sci USA , 2003). Partial detergent dissociation provided evidence for how these components are arranged in the full protease complex (Fraering et al. Biochemistry, 2004). Ongoing projects are focused on advancing the biochemistry of intramembrane proteases to establish general mechanistic principles as well as strategies for inhibitor design.

References:

W. P. Esler and M. S. Wolfe. Portraits of Alzheimer Secretases: New Features and Familiar Faces. Science 2001 , 293 , 1449-54.

W. P Esler, W. T. Kimberly, B. L. Ostaszewski, W. Ye, T. S. Diehl, D. J. Selkoe, and M. S. Wolfe. Activity-dependent isolation of the presenilin/ γ-secretase complex reveals nicastrin and a γ substrate. Proc. Natl. Acad. Sci. USA 2002 , 99 , 2720-5.

M. S. Wolfe and D. J. Selkoe. Intramembrane proteases: Mixing oil and water. Science 2002 , 296 , 2156-7.

W. T. Kimberly, B. L. Ostaszewski, W. Ye, M. J. LaVoie, M. S. Wolfe and D. J. Selkoe.γ-Secretase is a membrane protein complex of presenilin, nicastrin, aph-1 and pen-2. Proc. Natl. Acad. Sci. USA 2003 , 100 , 6382-7.

C. Das, O. Berezovska, T. S. Diehl, C. Genet, I. Buldyrev, J.-Y. Tsai, B. T. Hyman and M. S. Wolfe. Designed helical peptides inhibit an intramembrane protease. J. Am. Chem. Soc. 2003 , 125 , 11794-5.

P. C. Fraering, M. J. LaVoie, W. Ye, B. L. Ostaszewski, L. M. Magnotti, W. T. Kimberly, D. J. Selkoe and M. S. Wolfe. Detergent-dependent dissociation of active γ-secretase reveals an interaction between Pen-2 and PS1-NTF and offers a model for subunit organization within the complex. Biochemistry , 2004 , 43 , 323-33.

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