scholarly journals Die Endozytose — ein zellulärer Aufnahmeweg mit vielfältigen Funktionen

BIOspektrum ◽  
2021 ◽  
Vol 27 (6) ◽  
pp. 598-600
Author(s):  
Tanja Maritzen
Keyword(s):  
Brain Function ◽  
Ion Homeostasis ◽  
Transmembrane Proteins ◽  
Cell Stress ◽  
Cellular Functions ◽  
Neuronal Communication ◽  
Plastic Changes ◽  
Cellular Behaviour ◽  
Surface Proteome ◽  
Powerful Mechanism

AbstractThe plasma membrane harbors a specific set of transmembrane proteins which enable diverse cellular functions such as nutrient uptake, ion homeostasis and cellular signaling. The surface levels of these proteins need to be dynamically regulated to allow for plastic changes in cellular behaviour e. g. upon cell stress or during neuronal communication. Endocytosis is a powerful mechanism for quickly adapting the surface proteome via protein internalization. Here, I discuss how endocytosis contributes to brain function and counteracts cell stress.

scholarly journals Functional Aspects of Seminal Plasma in Bird Reproduction

2020 ◽  
Vol 21 (16) ◽  
pp. 5664
Author(s):  
Julian Santiago-Moreno ◽  
Elisabeth Blesbois
Keyword(s):  
Seminal Plasma ◽  
Ion Homeostasis ◽  
Sperm Concentration ◽  
Cellular Functions ◽  
Functional Aspects ◽  
Reproductive Techniques ◽  
Sperm Survival ◽  
Protein Components ◽  
And Function

This review provides an updated overview of the seminal plasma composition, and the role of metabolic and protein components on the sperm function of avian species. In addition, the implication of seminal plasma on assisted reproductive techniques of birds was discussed. The semen of birds usually has exceptionally high sperm concentration with relatively little seminal plasma, but this contributes to very fast changes in sperm metabolism and function. The biochemical characteristics and physiological roles of the various seminal plasma components in birds (carbohydrates, lipids, amino acids, hormones, and proteins) are poorly understood. Seminal plasma content of proteins has an action on most cellular functions: metabolism, immunity, oxido-reduction regulation, proteolysis, apoptosis, ion homeostasis, and antimicrobial defenses. The variable amount of many proteins is related to a different fertility capacity of poultry sperm. The role of seminal plasma on semen conservation (chilling and freezing) remains largely a matter of speculation, as both inhibitory and stimulating effects have been found. Whereas the presence of seminal plasma did not seem to affect the sperm survival after freezing–thawing, DNA fragmentation is lower in the absence of seminal plasma. The molecular basis of the influence of seminal plasma on sperm cryo-resistance was also discussed in the present review.

scholarly journals Mvb12 Is a Novel Member of ESCRT-I Involved in Cargo Selection by the Multivesicular Body Pathway

2007 ◽  
Vol 18 (2) ◽  
pp. 646-657 ◽  
Author(s):  
Andrea J. Oestreich ◽  
Brian A. Davies ◽  
Johanna A. Payne ◽  
David J. Katzmann
Keyword(s):  
Normal Cell ◽  
Transmembrane Proteins ◽  
Multivesicular Body ◽  
Eukaryotic Cells ◽  
Cell Physiology ◽  
Cellular Functions ◽  
Protein Loss ◽  
Endosomal Sorting ◽  
Vacuolar Protein ◽  
Selection Of

The multivesicular body (MVB) sorting pathway impacts a variety of cellular functions in eukaryotic cells. Perhaps the best understood role for the MVB pathway is the degradation of transmembrane proteins within the lysosome. Regulation of cargo selection by this pathway is critically important for normal cell physiology, and recent advances in our understanding of this process have highlighted the endosomal sorting complexes required for transport (ESCRTs) as pivotal players in this reaction. To better understand the mechanisms of cargo selection during MVB sorting, we performed a genetic screen to identify novel factors required for cargo-specific selection by this pathway and identified the Mvb12 protein. Loss of Mvb12 function results in differential defects in the selection of MVB cargoes. A variety of analyses indicate that Mvb12 is a stable member of ESCRT-I, a heterologous complex involved in cargo selection by the MVB pathway. Phenotypes displayed upon loss of Mvb12 are distinct from those displayed by the previously described ESCRT-I subunits (vacuolar protein sorting 23, -28, and -37), suggesting a distinct function than these core subunits. These data support a model in which Mvb12 impacts the selection of MVB cargoes by modulating the cargo recognition capabilities of ESCRT-I.

scholarly journals “Every cloud …”

2000 ◽  
Vol 176 (5) ◽  
pp. 412-413 ◽  
Author(s):  
Ian H. Robertson
Keyword(s):  
Early Childhood ◽  
Brain Function ◽  
Clinical Work ◽  
Adult Brain ◽  
Monday Morning ◽  
Dinner Party ◽  
Work Related ◽  
The Common ◽  
Plastic Changes ◽  
The Brain

Those involved in research or clinical work related to brain function will be used to the dinner party question “we only use 50% of the brain, don't we?” The scientist's dismissive sneer is usually well enough concealed, depending on how much he or she has had to drink. Where on earth did this lay myth arise, we chuckle over coffee in the common room on Monday morning? But scientists and clinicians are not immune to myths also. For many decades, neuroscientists preached the doctrine that the adult brain is ‘hard-wired’. Perhaps in very early childhood, we conceded, plastic changes in the brain were possible, but after the age of three or four years connections were indelibly made.

scholarly journals Distinct cellular and subcellular patterns of expression imply distinct functions for the Drosophila homologues of moesin and the neurofibromatosis 2 tumor suppressor, merlin.

1996 ◽  
Vol 133 (4) ◽  
pp. 843-852 ◽  
Author(s):  
B M McCartney ◽  
R G Fehon
Keyword(s):  
Tumor Suppressor ◽  
Cultured Cells ◽  
Transmembrane Proteins ◽  
Suppressor Gene ◽  
Cellular Functions ◽  
Neurofibromatosis 2 ◽  
Specific Antibodies ◽  
Protein 4.1 ◽  
Family Protein ◽  
Endocytic Compartments

Interest in members of the protein 4.1 super-family, which includes the ezrin-radixin-moesin (ERM) group, has been stimulated recently by the discovery that the human neurofibromatosis 2 (NF2) tumor suppressor gene encodes an ERM-like protein, merlin. Although many proteins in this family are thought to act by linking the actin-based cytoskeleton to transmembrane proteins, the cellular functions of merlin have not been defined. To investigate the cellular and developmental functions of these proteins, we have identified and characterized Drosophila homologues of moesin (Dmoesin) and of the NF2 tumor suppressor merlin (Dmerlin). Using specific antibodies, we show that although these proteins are frequently coexpressed in developing tissues, they display distinct subcellular localizations. While Dmoesin is observed in continuous association with the plasma membrane, as is typical for an ERM family protein, Dmerlin is found in punctuate structures at the membrane and in the cytoplasm. Investigation of Dmerlin cultured cells demonstrates that it is associated with endocytic compartments. As a result of these studies, we propose that the merlin protein has unique functions in the cell which differ from those of other ERM family members.

scholarly journals Pathophysiological Role of K2P Channels in Human Diseases

2021 ◽  
Vol 55 (S3) ◽  
pp. 65-86
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Expression Patterns ◽  
Ion Homeostasis ◽  
Human Diseases ◽  
Cellular Functions ◽  
Aberrant Expression ◽  
K2p Channels ◽  
And Function

The family of two-pore domain potassium (K2P) channels is critically involved in central cellular functions such as ion homeostasis, cell development, and excitability. K2P channels are widely expressed in different human cell types and organs. It is therefore not surprising that aberrant expression and function of K2P channels are related to a spectrum of human diseases, including cancer, autoimmune, CNS, cardiovascular, and urinary tract disorders. Despite homologies in structure, expression, and stimulus, the functional diversity of K2P channels leads to heterogeneous influences on human diseases. The role of individual K2P channels in different disorders depends on expression patterns and modulation in cellular functions. However, an imbalance of potassium homeostasis and action potentials contributes to most disease pathologies. In this review, we provide an overview of current knowledge on the role of K2P channels in human diseases. We look at altered channel expression and function, the potential underlying molecular mechanisms, and prospective research directions in the field of K2P channels.

Mechanisms of cell survival in hypoxia and hypothermia

2001 ◽  
Vol 204 (18) ◽  
pp. 3171-3181 ◽  
Author(s):  
R. G. Boutilier
Keyword(s):  
Experimental Approach ◽  
Membrane Damage ◽  
Ion Homeostasis ◽  
Deep Hypothermia ◽  
Cellular Functions ◽  
Ambient Exposure ◽  
Circulatory Insufficiency ◽  
Cold Tolerant ◽  
Atp Supply ◽  
The Brain

SUMMARYMost animals experience some degree of hypoxia and hypothermia during the course of their natural life history either as a consequence of ambient ‘exposure’ per se or through metabolic, respiratory and/or circulatory insufficiency. A prevailing experimental approach has been to probe tissues from natural models of hypoxia-tolerant and cold-tolerant vertebrates to look for common mechanisms of defence against O2 lack and hypothermia. The ability to sustain vital cellular functions in severe cases of either condition varies widely amongst the vertebrates. Like humans, the vast majority of mammals are unable to survive prolonged periods of hypothermia or O2 deprivation owing to irreversible membrane damage and loss of cellular ion homeostasis in vital organs such as the brain and heart. However, numerous hibernating endotherms, neonatal and diving mammals as well as many ectotherms can tolerate prolonged periods that would, in clinical terms, be called asphyxia or deep hypothermia. The key to their survival under such conditions lies in an inherent ability to downregulate their cellular metabolic rate to new hypometabolic steady states in a way that balances the ATP demand and ATP supply pathways.

Extracellular Calcium Sensing and Extracellular Calcium Signaling

2001 ◽  
Vol 81 (1) ◽  
pp. 239-297 ◽  
Author(s):  
Edward M. Brown ◽  
R. John MacLeod
Keyword(s):  
Cellular Proliferation ◽  
Bone Cells ◽  
Ion Homeostasis ◽  
Extracellular Fluid ◽  
Extracellular Calcium ◽  
Cellular Functions ◽  
Control Of Gene Expression ◽  
Activating Mutations ◽  
Calcium Sensing ◽  
Extracellular Ions

The cloning of a G protein-coupled extracellular Ca2+(Cao2+)-sensing receptor (CaR) has elucidated the molecular basis for many of the previously recognized effects of Cao2+on tissues that maintain systemic Cao2+homeostasis, especially parathyroid chief cells and several cells in the kidney. The availability of the cloned CaR enabled the development of DNA and antibody probes for identifying the CaR's mRNA and protein, respectively, within these and other tissues. It also permitted the identification of human diseases resulting from inactivating or activating mutations of the CaR gene and the subsequent generation of mice with targeted disruption of the CaR gene. The characteristic alterations in parathyroid and renal function in these patients and in the mice with “knockout” of the CaR gene have provided valuable information on the CaR's physiological roles in these tissues participating in mineral ion homeostasis. Nevertheless, relatively little is known about how the CaR regulates other tissues involved in systemic Cao2+homeostasis, particularly bone and intestine. Moreover, there is evidence that additional Cao2+sensors may exist in bone cells that mediate some or even all of the known effects of Cao2+on these cells. Even more remains to be learned about the CaR's function in the rapidly growing list of cells that express it but are uninvolved in systemic Cao2+metabolism. Available data suggest that the receptor serves numerous roles outside of systemic mineral ion homeostasis, ranging from the regulation of hormonal secretion and the activities of various ion channels to the longer term control of gene expression, programmed cell death (apoptosis), and cellular proliferation. In some cases, the CaR on these “nonhomeostatic” cells responds to local changes in Cao2+taking place within compartments of the extracellular fluid (ECF) that communicate with the outside environment (e.g., the gastrointestinal tract). In others, localized changes in Cao2+within the ECF can originate from several mechanisms, including fluxes of calcium ions into or out of cellular or extracellular stores or across epithelium that absorb or secrete Ca2+. In any event, the CaR and other receptors/sensors for Cao2+and probably for other extracellular ions represent versatile regulators of numerous cellular functions and may serve as important therapeutic targets.

scholarly journals A Rationale for Hypoxic and Chemical Conditioning in Huntington’s Disease

2021 ◽  
Vol 22 (2) ◽  
pp. 582
Author(s):  
Johannes Burtscher ◽  
Vittorio Maglione ◽  
Alba Di Pardo ◽  
Grégoire P. Millet ◽  
Christoph Schwarzer ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Drug Targets ◽  
Ion Homeostasis ◽  
Brain Regions ◽  
Molecular Pathways ◽  
Cellular Functions ◽  
Cellular Environment ◽  
Δ Opioid Receptor

Neurodegenerative diseases are characterized by adverse cellular environments and pathological alterations causing neurodegeneration in distinct brain regions. This development is triggered or facilitated by conditions such as hypoxia, ischemia or inflammation and is associated with disruptions of fundamental cellular functions, including metabolic and ion homeostasis. Targeting intracellular downstream consequences to specifically reverse these pathological changes proved difficult to translate to clinical settings. Here, we discuss the potential of more holistic approaches with the purpose to re-establish a healthy cellular environment and to promote cellular resilience. We review the involvement of important molecular pathways (e.g., the sphingosine, δ-opioid receptor or N-Methyl-D-aspartate (NMDA) receptor pathways) in neuroprotective hypoxic conditioning effects and how these pathways can be targeted for chemical conditioning. Despite the present scarcity of knowledge on the efficacy of such approaches in neurodegeneration, the specific characteristics of Huntington’s disease may make it particularly amenable for such conditioning techniques. Not only do classical features of neurodegenerative diseases like mitochondrial dysfunction, oxidative stress and inflammation support this assumption, but also specific Huntington’s disease characteristics: a relatively young age of neurodegeneration, molecular overlap of related pathologies with hypoxic adaptations and sensitivity to brain hypoxia. The aim of this review is to discuss several molecular pathways in relation to hypoxic adaptations that have potential as drug targets in neurodegenerative diseases. We will extract the relevance for Huntington’s disease from this knowledge base.

scholarly journals Multichannel optogenetics combined with laminar recordings for ultra-controlled neuronal interrogation

2021 ◽  
Author(s):  
David Eriksson ◽  
Artur Schneider ◽  
Anupriya Thirumalai ◽  
Mansour Alyahyaey ◽  
Brice de la Crompe ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Brain Function ◽  
Large Scale ◽  
High Quality ◽  
Brain Areas ◽  
New Techniques ◽  
Neuronal Communication ◽  
Flexible Fiber ◽  
Freely Moving ◽  
New Framework

Abstract Highlights: To combine large-scale recordings with optical perturbation we have developed a number of new techniques such as thin optical side-emitting fibers, a fiber matrix connector for thin fibers, an electro-optical commutator for multiple thin fibers, an active patch cord, a flexible fiber bundle ribbon cable, and a modular multi-optrode implantation holder.Summary: Simultaneous large-scale recordings and optogenetic interventions hold the promise to decipher the fast-paced and multifaceted dialogue between neurons that sustains brain function. Here we developed unprecedentedly thin, cell-sized Lambertian side-emitting optical fibers and combined them with silicon probes to achieve high quality recordings and ultrafast multichannel optogenetic inhibition in freely moving animals. Our new framework paves the way for large-scale photo tagging and controlled interrogation of rapid neuronal communication in any combination of brain areas.

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