6U7M

Cryo-EM Structure of Helical Lipoprotein Lipase

Summary for 6U7M

• Entry DOI: 10.2210/pdb6u7m/pdb
• EMDB information: 20673
• Descriptor: Lipoprotein lipase (1 entity in total)
• Functional Keywords: helical symmetry, lipoprotein lipase, protein fibril, hydrolase
• Biological source: Bos taurus (Bovine)
• Total number of polymer chains: 30
• Total formula weight: 1603463.67

Authors

Gunn, K.H.,Wang, F.,Egelman, E.H.,Neher, S.B. (deposition date: 2019-09-03, release date: 2020-04-08, Last modification date: 2025-05-21)

Primary citation

Gunn, K.H.,Roberts, B.S.,Wang, F.,Strauss, J.D.,Borgnia, M.J.,Egelman, E.H.,Neher, S.B.
The structure of helical lipoprotein lipase reveals an unexpected twist in lipase storage.
Proc.Natl.Acad.Sci.USA, 117:10254-10264, 2020

PubMed Abstract: Lipases are enzymes necessary for the proper distribution and utilization of lipids in the human body. Lipoprotein lipase (LPL) is active in capillaries, where it plays a crucial role in preventing dyslipidemia by hydrolyzing triglycerides from packaged lipoproteins. Thirty years ago, the existence of a condensed and inactive LPL oligomer was proposed. Although recent work has shed light on the structure of the LPL monomer, the inactive oligomer remained opaque. Here we present a cryo-EM reconstruction of a helical LPL oligomer at 3.8-Å resolution. Helix formation is concentration-dependent, and helices are composed of inactive dihedral LPL dimers. Heparin binding stabilizes LPL helices, and the presence of substrate triggers helix disassembly. Superresolution fluorescent microscopy of endogenous LPL revealed that LPL adopts a filament-like distribution in vesicles. Mutation of one of the helical LPL interaction interfaces causes loss of the filament-like distribution. Taken together, this suggests that LPL is condensed into its inactive helical form for storage in intracellular vesicles.

PubMed: 32332168
DOI: 10.1073/pnas.1916555117

Experimental method

ELECTRON MICROSCOPY (3.8 Å)