Polarized trafficking: the palmitoylation cycle distributes cytoplasmic proteins to distinct neuronal compartments

Adipogenesis and osteoblastogenesis (adipo-osteoblastogenesis) are closely related processes involving with the phosphorylation of numerous cytoplasmic proteins and key transcription factors.

Download Full-text

Lipid Transporters Beam Signals from Cell Membranes

Membranes ◽

10.3390/membranes11080562 ◽

2021 ◽

Vol 11 (8) ◽

pp. 562

Author(s):

Miliça Ristovski ◽

Danny Farhat ◽

Shelly Ellaine M. Bancud ◽

Jyh-Yeuan Lee

Keyword(s):

Membrane Proteins ◽

Lipid Bilayers ◽

Lipid Composition ◽

Structural Integrity ◽

Current Knowledge ◽

Integral Membrane Proteins ◽

Cellular Membranes ◽

Cytoplasmic Proteins ◽

Lipid Transporters

Lipid composition in cellular membranes plays an important role in maintaining the structural integrity of cells and in regulating cellular signaling that controls functions of both membrane-anchored and cytoplasmic proteins. ATP-dependent ABC and P4-ATPase lipid transporters, two integral membrane proteins, are known to contribute to lipid translocation across the lipid bilayers on the cellular membranes. In this review, we will highlight current knowledge about the role of cholesterol and phospholipids of cellular membranes in regulating cell signaling and how lipid transporters participate this process.

Download Full-text

Amikacin and bacteriophage treatment modulates outer membrane proteins composition in Proteus mirabilis biofilm

Scientific Reports ◽

10.1038/s41598-020-80907-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Agnieszka Maszewska ◽

Magdalena Moryl ◽

Junli Wu ◽

Bin Liu ◽

Lu Feng ◽

...

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Proteus Mirabilis ◽

Protein Biosynthesis ◽

Outer Membrane Proteins ◽

Wild Strain ◽

Elongation Factor ◽

Resistance Mechanisms ◽

Trna Synthetases ◽

Cytoplasmic Proteins

AbstractModification of outer membrane proteins (OMPs) is the first line of Gram-negative bacteria defence against antimicrobials. Here we point to Proteus mirabilis OMPs and their role in antibiotic and phage resistance. Protein profiles of amikacin (AMKrsv), phage (Brsv) and amikacin/phage (AMK/Brsv) resistant variants of P. mirabilis were compared to that obtained for a wild strain. In resistant variants there were identified 14, 1, 5 overexpressed and 13, 5, 1 downregulated proteins for AMKrsv, Brsv and AMK/Brsv, respectively. Application of phages with amikacin led to reducing the number of up- and downregulated proteins compared to single antibiotic treatment. Proteins isolated in AMKrsv are involved in protein biosynthesis, transcription and signal transduction, which correspond to well-known mechanisms of bacteria resistance to aminoglycosides. In isolated OMPs several cytoplasmic proteins, important in antibiotic resistance, were identified, probably as a result of environmental stress, e.g. elongation factor Tu, asparaginyl-tRNA and aspartyl-tRNA synthetases. In Brsv there were identified: NusA and dynamin superfamily protein which could play a role in bacteriophage resistance. In the resistant variants proteins associated with resistance mechanisms occurring in biofilm, e.g. polyphosphate kinase, flagella basal body rod protein were detected. These results indicate proteins important in the development of P. mirabilis antibiofilm therapies.

Download Full-text

Thiol-sensitive sites in cell adhesion. Decreased entry of SH-binding reagents into attached BHK cells

Biochemical Journal ◽

10.1042/bj2080473 ◽

1982 ◽

Vol 208 (2) ◽

pp. 473-478 ◽

Cited By ~ 7

Author(s):

D D McAbee ◽

F Grinnell

Keyword(s):

Cell Adhesion ◽

Small Molecules ◽

Cell Spreading ◽

The Other ◽

Bhk Cells ◽

Sh Groups ◽

Nitrobenzoic Acid ◽

Cytoplasmic Proteins ◽

Adhesion Process ◽

Suspended Cells

Studies were carried out to learn more about the critical SH groups involved in cell spreading. Pretreatment of suspended baby hamster kidney (BHK) cells with 3 mM-iodoacetate or iodoacetamide for 10 min at 4 degrees C completely inhibited the ability of the cells to spread on fibronectin-coated substrata. If, however, BHK cells were permitted to attach and spread before being treated with the SH-binding reagents, and then harvested by trypsinization and assayed for spreading on fibronectin-coated substrata, there was no inhibition of cell spreading. The extent of prior attachment required before the cells became insensitive to the SH-binding reagents was tested and was found to occur early during the cell adhesion process, before any cell spreading was observed. In analytical experiments, there did not appear to be any difference in the total number of SH groups between suspended or spread cells as determined with 5,5′-dithiobis-(2-nitrobenzoic acid). The uptake of radiolabelled iodoacetate into intact spread cells, however, was found to be 3.5 times less than that found with suspended cells. On the other hand, the distribution of incorporated radioactivity into suspended and spread cells was similar. Most of the radioactivity (approximately 70%) was incorporated into small molecules (e.g. glutathione and cysteine), less (approximately 20%) was incorporated into cytoplasmic proteins, and the least incorporation (approximately 10%) was into the cell cytoskeleton. The data are interpreted to indicate there is a decreased permeability of spread cells to the SH-binding reagents.

Download Full-text

Proteostatic regulation in neuronal compartments

Trends in Neurosciences ◽

10.1016/j.tins.2021.08.002 ◽

2021 ◽

Author(s):

Stefano L. Giandomenico ◽

Beatriz Alvarez-Castelao ◽

Erin M. Schuman

Keyword(s):

Neuronal Compartments

Download Full-text

Extracellular Vesicles-Encapsulated Yeast Prions and What They Can Tell Us about the Physical Nature of Propagons

International Journal of Molecular Sciences ◽

10.3390/ijms22010090 ◽

2020 ◽

Vol 22 (1) ◽

pp. 90

Author(s):

Mehdi Kabani

Keyword(s):

Protein Quality ◽

Fluorescent Protein ◽

Physical Nature ◽

Dependent Manner ◽

Yeast Saccharomyces Cerevisiae ◽

Yeast Prions ◽

Daughter Cells ◽

Cytoplasmic Proteins ◽

Green Fluorescent ◽

Functionally Diverse

The yeast Saccharomyces cerevisiae hosts an ensemble of protein-based heritable traits, most of which result from the conversion of structurally and functionally diverse cytoplasmic proteins into prion forms. Among these, [PSI+], [URE3] and [PIN+] are the most well-documented prions and arise from the assembly of Sup35p, Ure2p and Rnq1p, respectively, into insoluble fibrillar assemblies. Yeast prions propagate by molecular chaperone-mediated fragmentation of these aggregates, which generates small self-templating seeds, or propagons. The exact molecular nature of propagons and how they are faithfully transmitted from mother to daughter cells despite spatial protein quality control are not fully understood. In [PSI+] cells, Sup35p forms detergent-resistant assemblies detectable on agarose gels under semi-denaturant conditions and cytosolic fluorescent puncta when the protein is fused to green fluorescent protein (GFP); yet, these macroscopic manifestations of [PSI+] do not fully correlate with the infectivity measured during growth by the mean of protein infection assays. We also discovered that significant amounts of infectious Sup35p particles are exported via extracellular (EV) and periplasmic (PV) vesicles in a growth phase and glucose-dependent manner. In the present review, I discuss how these vesicles may be a source of actual propagons and a suitable vehicle for their transmission to the bud.

Download Full-text