Tepsin binds LC3B to promote ATG9A trafficking and delivery.

Tepsin is an established accessory protein found in Adaptor Protein 4 (AP-4) coated vesicles, but the biological role of tepsin remains unknown. AP-4 vesicles originate at the -Golgi network (TGN) and target the delivery of ATG9A, a scramblase required for autophagosome biogenesis, to the cell periphery. Using in silico methods, we identified a putative C3-nteracting egion (LIR) motif in tepsin.

Tepsin binds LC3B to promote ATG9A export and delivery at the cell periphery.

Tepsin is an established accessory protein found in Adaptor Protein 4 (AP-4) coated vesicles, but the biological role of tepsin remains unknown. AP-4 vesicles originate at the -Golgi network (TGN) and target the delivery of ATG9A, a scramblase required for autophagosome biogenesis, to the cell periphery. Using methods, we identified a putative L C3-Interacting R egion (LIR) motif in tepsin.

Integrating structural and evolutionary data to interpret variation and pathogenicity in adapter protein complex 4.

Genetic variation in the membrane trafficking adapter protein complex 4 (AP-4) can result in pathogenic neurological phenotypes including microencephaly, spastic paraplegias, epilepsy, and other developmental defects. We lack molecular mechanisms responsible for impaired AP-4 function arising from genetic variation, because AP-4 remains poorly understood structurally. Here, we analyze patterns of AP-4 genetic evolution and conservation to identify regions that are likely important for function and thus more susceptible to pathogenic variation.

IpdE1-IpdE2 Is a Heterotetrameric Acyl Coenzyme A Dehydrogenase That Is Widely Distributed in Steroid-Degrading Bacteria.

Steroid-degrading bacteria, including (), utilize an architecturally distinct subfamily of acyl coenzyme A dehydrogenases (ACADs) for steroid catabolism. These ACADs are αβ heterotetramers that are usually encoded by adjacent like genes. In mycobacteria, and (formerly and ) occur in divergently transcribed operons associated with the catabolism of 3aα--4α(3'-propanoate)-7aβ-methylhexahydro-1,5-indanedione (HIP), a steroid metabolite.

A mass spectrometry-based isotope-coded mass tag method to map thiol accessibility in biological systems.

Interactions at biological membranes are important for many cellular functions, but because of the dynamic nature of these interactions, traditional methods of structure investigation are limited. Here, we describe a method that utilizes thiol-maleimide chemistry to monitor the solvent-accessible surface of membrane-protein complexes and membrane dynamics in vitro in real time. This method, called the isotope-coded mass tag (ICMT) method, has been used previously to locate thiols in transmembrane peptides, to elucidate lipid flipping kinetics in bilayers, to determine the oxidation state of disulfide bonds, and to investigate the protein-lipid interface of the peripheral membrane protein cholesterol oxidase.

Use of an Isotope-Coded Mass Tag (ICMT) Method To Determine the Orientation of Cholesterol Oxidase on Model Membranes.

Although the interfacial membrane protein cholesterol oxidase is structurally and kinetically well-characterized, its orientation in and mode of interaction with cholesterol-containing membranes have not been established. Cholesterol oxidase can alter the structure of the cell membrane in pathogenic bacteria and is thus a potential antimicrobial drug target. We recently developed a mass spectrometry-based isotope-coded mass tag (ICMT) labeling method to monitor the real-time solvent-accessible surface of peripheral membrane proteins, such as cholesterol oxidase.

Diacyltransferase Activity and Chain Length Specificity of Mycobacterium tuberculosis PapA5 in the Synthesis of Alkyl β-Diol Lipids.

Although they are classified as Gram-positive bacteria, Corynebacterineae possess an asymmetric outer membrane that imparts structural and thereby physiological similarity to more distantly related Gram-negative bacteria. Like lipopolysaccharide in Gram-negative bacteria, lipids in the outer membrane of Corynebacterineae have been associated with the virulence of pathogenic species such as Mycobacterium tuberculosis (Mtb). For example, Mtb strains that lack long, branched-chain alkyl esters known as dimycocerosates (DIMs) are significantly attenuated in model infections.