Studying protein unfolding and translocation by the protease FtsH with optical tweezers

The protease FtsH is a membrane anchored protease that degrades misfolded (membrane) proteins. To study the mechanism behind unfolding and translocation with optical tweezers, the protease had to be purified. However, full-length FtsH has hardly been studied as solubilizing this membrane anchored protease is challenging. Our group (Dr. V....

Divide and Conquer: A Tailored Solid-state NMR Approach to Study Large Membrane Protein Complexes

Membrane proteins are known to exert many essential biological functions by forming complexes in cell membranes. An example refers to the β-barrel assembly machinery (BAM), a 200 kDa pentameric complex containing BAM proteins A–E that catalyzes the essential process of protein insertion into the outer membrane of gram-negative bacteria. While...

Rhodopsins: An Excitingly Versatile Protein Species for Research, Development and Creative Engineering

The first member and eponym of the rhodopsin family was identified in the 1930s as the visual pigment of the rod photoreceptor cell in the animal retina. It was found to be a membrane protein, owing its photosensitivity to the presence of a covalently bound chromophoric group. This group, derived from vitamin A, was appropriately dubbed retinal....

Reconstitution and functional characterization of the FtsH protease in lipid nanodiscs

FtsH is a membrane-bound protease that plays a crucial role in proteolytic regulation of many cellular functions. It is universally conserved in bacteria and responsible for the degradation of misfolded or misassembled proteins. A recent study has determined the structure of bacterial FtsH in detergent micelles. To properly study the function...

Peripheral membrane proteins: Promising therapeutic targets across domains of life

Membrane proteins can be classified into two main categories—integral and peripheral membrane proteins—depending on the nature of their membrane interaction. Peripheral membrane proteins are highly unique amphipathic proteins that interact with the membrane indirectly, using electrostatic or hydrophobic interactions, or directly, using...

Influence of Assay Parameters on Structural and Functional Studies of Membrane Proteins

Structural and functional characterization of membrane proteins (MPs) requires extraction from the native lipid bilayer, which generally necessitates the formation of water-soluble MPs structures or complexes suitable for biochemical assays. These structures are often detergent micelles that form protein-detergent complexes (PDCs), due to...

Interactions between model inclusions on closed lipid bilayer membranes

Protein inclusions in the membranes of living cells interact via the deformations they impose on that membrane. Such membrane-mediated interactions lead to sorting and self-assembly of the inclusions, as well as to membrane remodelling, crucial for many biological processes. For the past decades, theory, numerical calculations and experiments...

Biochemical and structural studies of FtsH, a membrane anchored degradation machine

Proteins are one of the most important constituents of cells, since they are responsible for various processes such as replication, translation, etc. Interestingly, proteins are also responsible for the degradation of proteins that do not assemble well, and/or which are not necessary anymore inside the cell. This process of proteins destruction...

Aquaporin-2 trafficking: Studying cellular mechanisms with subcellular aspiration and cryo-electron microscopy

The Amyloid Precursor Protein (APP) Does Not Have a Ferroxidase Site in Its E2 Domain

The ubiquitous 24-meric iron-storage protein ferritin and multicopper oxidases such as ceruloplasmin or hephaestin catalyze oxidation of Fe(II) to Fe(III), using molecular oxygen as oxidant. The ferroxidase activity of these proteins is essential for cellular iron homeostasis. It has been reported that the amyloid precursor protein (APP) also...