Treatment of purified Ehrlich ascites cell plasma membranes either with [3H]cytochalasin B or [3H]19-O-acetylchaetoglobosin A under photolytic conditions produced several radioactive polypeptides which were characterized by SDS-PAGE analyses. The major proteins so photolabeled were in the 60,000-80,000 Da range, with less labeling found in polypeptides smaller than 43,000 and greater than 90,000 Da. Immunofluorescent staining failed to identify the major photolabeled component as actin. It is concluded, in keeping with prior investigations using other cell types, that the predominant proteins photolabeled by cytochalasins are affiliated with the glucose-transport system.
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http://dx.doi.org/10.1016/0300-9084(88)90060-0 | DOI Listing |
Q Rev Biophys
January 2025
Faculty of Medicine, Department of Biophysics and Neuroscience, Wroclaw Medical University, Wrocław, Poland.
The GABA type A receptor (GABAR) belongs to the family of pentameric ligand-gated ion channels and plays a key role in inhibition in adult mammalian brains. Dysfunction of this macromolecule may lead to epilepsy, anxiety disorders, autism, depression, and schizophrenia. GABAR is also a target for multiple physiologically and clinically relevant modulators, such as benzodiazepines (BDZs), general anesthetics, and neurosteroids.
View Article and Find Full Text PDFNat Commun
November 2024
Novo Nordisk Research Center Seattle, Inc., Seattle, WA, USA.
C-terminal α-amidated peptides are attractive therapeutic targets, but preparative methods to access amidated pharmaceuticals are limited both on lab and manufacturing-scale. Here we report a straightforward and scalable approach to the C-terminal α-amidation of peptides and proteins from cysteine-extended polypeptide precursors. This amidation protocol consists of three highly efficient steps: 1) selective cysteine thiol substitution with a photolabel, 2) photoinduced decarboxylative elimination and 3) enamide cleavage by simple acidolysis or inverse electron demand Diels-Alder reaction.
View Article and Find Full Text PDFRSC Adv
November 2024
Department of Developmental Biology, Washington University in St. Louis 660 S. Euclid Ave. St. Louis MO 63110 USA
The endogenous neurosteroids dehydroepiandrosterone sulfate (DHEAS) and pregnenolone sulfate (PS) are allosteric modulators of γ-aminobutyric acid type A (GABA) and -methyl-d-aspartate (NMDA) type glutamate receptors. Analogues of these endogenous steroid sulfates can be either positive or negative allosteric modulators (PAMs or NAMs, respectively) of these receptors, but there is limited information about the steroid-protein binding interactions that mediate these effects and photoaffinity labeling reagents (PALs) of sulfated steroids have not been reported previously. The synthesis of a panel of ten sulfated steroid analogues containing a diazirine group, five of which also contain an alkyne group for click chemistry reactions, for use in photoaffinity labeling studies to identify binding sites for steroid sulfates that are either positive or negative allosteric modulators is reported.
View Article and Find Full Text PDFJCI Insight
October 2024
Laboratory of Immunology, Faculty of Pharmacy, Osaka Ohtani University, Tondabayashi, Osaka, Japan.
The oral mucosa is the first line of defense against pathogenic bacteria and plays a vital role in maintaining tolerance to food antigens and commensal bacteria. We used CD11c reporter mice to visualize dendritic cells (DCs), a key immune cell population, in the oral cavity. We identified differences in DC density in each oral tissue region.
View Article and Find Full Text PDFJ Biol Chem
October 2024
Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri, USA; Department of Developmental Biology, Washington University School of Medicine, St Louis, Missouri, USA; The Taylor Family Institute for Innovative Psychiatric Research Washington University School of Medicine, St Louis, Missouri, USA. Electronic address:
Propofol is a widely used anesthetic and sedative that acts as a positive allosteric modulator of gamma-aminobutyric acid type A (GABA) receptors. Several potential propofol binding sites that may mediate this effect have been identified using propofol-analogue photoaffinity labeling. Ortho-propofol diazirine (o-PD) labels β-H267, a pore-lining residue, whereas AziPm labels residues β-M286, β-M227, and α-I239 in the two membrane-facing interfaces [β(+)/α(-) and α(+)/β(-)] between α and β subunits.
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