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Endolysosomal Patch Clamping
Published in Bruno Gasnier, Michael X. Zhu, Ion and Molecule Transport in Lysosomes, 2020
Cheng-Chang Chen, Christian Grimm, Christian Wahl-Schott, Martin Biel
The endolysosomal system plays a major role in intracellular vesicle trafficking, degradation and ion homoeostasis. These processes regulate important functions in different types of cells, i.e. migration of tumour cells or inflammatory and infection response in immune cells. An ever increasing number of studies suggest that endolysosomal membrane proteins are extremely critical for the function of the endolysosomal system. Dysfunction of these membrane proteins can impact or cause numerous human diseases, including neurodegenerative diseases, i.e. mucolipidosis type IV (MLIV) and Batten disease, metabolic diseases, infectious diseases and cancer.
Scanning Angle Interference Microscopy (SAIM)
Published in Qiu-Xing Jiang, New Techniques for Studying Biomembranes, 2020
Cristina Bertocchi, Timothy J. Rudge, Andrea Ravasio
Major advances in cell biology are strongly associated with innovations in microscopy due to its non-invasiveness that permits time-resolved imaging of live cells. In particular, high-resolution microscopy allows extraction of information about the structure–function relationship that is crucial for understanding molecular mechanisms in living cells. In the case of SAIM, axial precision, the ability to image multiple color channels, suitability for live cell imaging due to its dynamic capability, and adaptability to mechanically tuned cell substrates, makes it a useful method for exploration of the molecular mechanisms and topological arrangements underlying dynamic mechanical processes. SAIM is effective for measurement of distinct structures with a thickness <150 nm. This feature makes it perfectly suited for studying topography of plasma membranes and associated protein complexes (e.g., adhesive complexes), intracellular vesicle trafficking (such as exocytosis and endocytosis) associated to the membrane, and organization of cytoskeletal filaments and microtubules. Here we will highlight a few examples of the most recent applications of SAIM to answering biological questions.
Botulinum toxins: Pharmacology, immunology, and current developments
Published in Anthony V. Benedetto, Botulinum Toxins in Clinical Aesthetic Practice, 2017
Mechanistically, the universal process of SNARE-mediated synaptic vesicle trafficking is the ultimate pharmacological target for BoNTs in neurons that are capable of binding and internalizing the toxin.50
Understanding extracellular vesicle diversity – current status
Published in Expert Review of Proteomics, 2018
David W. Greening, Richard J. Simpson
Membrane proteins and lipids are often distributed in select regions on the cell surface. These regions are often assumed to be membrane domains, arising from specific molecular associations. Statistical simulations [199] suggest that membrane patchiness may result from a combination of vesicle trafficking and dynamic barriers to lateral mobility. When vesicle trafficking and endocytosis is inhibited, patches of integral membrane proteins and lipids on the cell surface increase, while their intensities decrease [200] – indicating a transient association between vesicle trafficking and cell surface membrane distribution. It is of note that in addition to their importance in vesicle trafficking, the budding process of sMVs appears to occur at specific sites on the PM and is designed to release select cellular components into the surrounding environment, particularly cargo involved in cell–matrix interactions and matrix degradation [201,202]. Functional proteomic analysis of lipid rafts using quantitative high-resolution mass spectrometry (MS) and cholesterol-disrupting drug treatments, revealed correlation with known signaling factors and vesicle trafficking proteins, including SNAP23 and flotillin-1 [203]. The origin of sMVs has been shown to occur from various origins on the PM, including at microvillar protrusions of intestinal epithelial cells [157] and from cells engineered to overexpress hyaluronan synthase [204], and from cilia [205].
Misdiagnosis of X-linked retinitis pigmentosa in a choroideremia patient with heavily pigmented fundi
Published in Ophthalmic Genetics, 2018
A. Nanda, A. P. Salvetti , C. Martinez-Fernandez de la Camara, R. E. MacLaren
Choroideremia affects 1 in 50,000 males and is a rare X-linked recessive retinal dystrophy. It is caused by mutations in the CHM gene, which encodes Rab Escort protein 1 (REP1). It is ubiquitously expressed and plays a fundamental role in intracellular vesicle trafficking (5). The REP1 protein is expressed in both photoreceptors and the retinal pigment epithelium, but the latter is considered the primary cell type that drives the degeneration (6). In retinitis pigmentosa, however, it is thought that the photoreceptor loss leads to pigmentary changes commonly referred to as 'bone spicules', due to migration of retinal pigment cells into the outer plexiform layer of the retina in regions devoid of photoreceptors (7,8). In retrospect, the complete absence of spicules and relatively normal vessel caliber and optic nerve appearance should have hinted to the fact that the photoreceptors might not have been the primary site of disease. Nevertheless in early stages, RPGR-related retinal degenerations have been described with patients showing the typical bone spicule formation as well as patients without (9). In the early stages of disease, it can be difficult to decipher the type of pigmentary change in darker skinned individuals, who typically have more pigmented fundi (10). Historically, most clinical signs have been described in Caucasian patients; therefore, in darker skinned choroideremia and RP patients, subtle changes may only become apparent in later stages of degeneration.
Relationship between the effect of polyunsaturated fatty acids (PUFAs) on brain plasticity and the improvement on cognition and behavior in individuals with autism spectrum disorder
Published in Nutritional Neuroscience, 2022
Isabel Barón-Mendoza, Aliesha González-Arenas
Vesicle trafficking is mainly regulated by SNARE (Soluble NSF Attachment Protein) proteins [131]. SNARE proteins are at vesicle membranes (v-SNAREs) as in target membranes (t-SNAREs). v-SNARE and t-SNARE pairing promotes the fusion of membranes by using the energy released during the formation of a trans-SNARE complex, which consists of a four α helix beam that allows the narrow approaching of membranes for the beginning of the fusion [132]. The specificity of this fusion mechanism is supported by the vesicle addressing to the target membrane by Rab proteins. Rab proteins are monomeric GTPases, which in its GTP-bound active state guide a vesicle to a specific target membrane for its following fusion [133].