The optical control over biological function with small photoswitchable molecules has gathered significant attention in the last decade. Herein, we describe the design and synthesis of a small library of photoswitchable peptidomimetics based upon human atrial natriuretic peptide (ANP), in which the photochromic amino acid [3-(3-aminomethyl)phenylazo]phenylacetic ...

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Two-photon laser scanning calcium imaging has emerged as a useful method for the exploration of neural function and structure at the cellular and subcellular level in vivo. The applications range from imaging of subcellular compartments such as dendrites, spines and axonal boutons up to the functional analysis of large neuronal or glial populations. However, the ...

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Förster resonance energy transfer (FRET) is a versatile method for analyzing protein–protein interactions within living cells. This protocol describes a nondestructive live-cell FRET assay for robust quantification of relative binding affinities for protein–protein interactions. Unlike other approaches, our method correlates the measured FRET efficiencies to ...

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Oligodendrocyte damage is a central event in the pathogenesis of the common neuroinflammatory condition, multiple sclerosis (MS). Where and how oligodendrocyte damage is initiated in MS is not completely understood. Here, we use a combination of light and electron microscopy techniques to provide a dynamic and highly resolved view of oligodendrocyte damage in ...

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Developmental axon remodeling is characterized by the selective removal of branches from axon arbors. The mechanisms that underlie such branch loss are largely unknown. Additionally, how neuronal resources are specifically assigned to the branches of remodeling arbors is not understood. Here we show that axon branch loss at the developing mouse neuromuscular ...

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The transmembrane helix of the amyloid precursor protein is subject to proteolytic cleavages by γ-secretase at different sites resulting in Aβ peptides of different length and toxicity. A number of point mutations within this transmembrane helix alter the cleavage pattern thus enhancing production of toxic Aβ peptide species that are at the root of familial ...

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Improved expansion microscopy provides a super-resolution method that is accessible to any laboratory with a fluorescence microscope.
 

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Programmed cell death is an integral component of Caenorhabditis elegans development. Genetic and reverse genetic studies in C. elegans have led to the identification of many genes and conserved cell death pathways that are important for the specification of which cells should live or die, the activation of the suicide program, and the dismantling and removal of ...

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Fluorescence resonance energy transfer (FRET) is a powerful method for the detection and quantification of stationary and dynamic protein-protein interactions. Technical limitations have hampered systematic in vivo FRET experiments to study protein-protein interactions in their native environment. Here, we describe a rapid and robust protocol that combines ...

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Increased levels of the second messenger lipid diacylglycerol (DAG) induce downstream signaling events including the translocation of C1-domain-containing proteins toward the plasma membrane. Here, we introduce three light-sensitive DAGs, termed PhoDAGs, which feature a photoswitchable acyl chain. The PhoDAGs are inactive in the dark and promote the translocation ...

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Neuronal mitochondria are receiving a rapidly increasing level of attention. This is to a significant part due to the ability to visualize neuronal mitochondria in novel ways, especially in vivo. Such an approach allows studying neuronal mitochondria in an intact tissue context, during different developmental states and in various genetic backgrounds and disease ...

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The arrangement of β cells within islets of Langerhans is critical for insulin release through the generation of rhythmic activity. A privileged role for individual β cells in orchestrating these responses has long been suspected, but not directly demonstrated. We show here that the β cell population in situ is operationally heterogeneous. Mapping of islet ...

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An essential feature of Alzheimer's disease (AD) is the accumulation of amyloid-β (Aβ) peptides in the brain, many years to decades before the onset of overt cognitive symptoms. We suggest that during this very extended early phase of the disease, soluble Aβ oligomers and amyloid plaques alter the function of local neuronal circuits and large-scale networks by ...

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Purpose: Preclinical studies on photoreceptor transplantation provided evidence for restoration of visual function with pluripotent stem cells considered as a potential source for sufficient amounts of donor material. Adequate preclinical models representing retinal disease conditions of potential future patients are needed for translation research. Here we ...

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Retinitis pigmentosa is an inherited blinding disorder characterized by progressive degeneration and loss of photoreceptors. The exact mechanism of degeneration and cell death of photoreceptors is not known, but is thought to involve disturbed Ca²⁺—signaling. Ca²⁺ can enter the photoreceptor cell via outer segment cyclic nucleotide-gated (CNG) channels or ...

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Sodium–calcium exchangers (NCXs) are membrane transporters that play an important role in Ca²⁺ homeostasis and Ca²⁺ signaling. The recent crystal structure of NCX_Mj, a member of the NCX family from the archaebacterium Methanococcus jannaschii, provided insight into the atomistic details of sodium–calcium exchange. Here, we extend these findings by providing ...

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Purpose: This study aims to identify which aspects of the pupil light reflex are most influenced by rods and cones independently by analyzing pupil recordings from different mouse models of photoreceptor deficiency.

Methods: One-month-old wild type (WT), rodless (Rho^−/−), coneless (Cnga3^−/−), or photoreceptor less (Cnga3^−/−; Rho^−/− or Gnat1^−/−) mice were ...

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Neuromyelitis optica (NMO) is an autoimmune disease of the central nervous system, which resembles multiple sclerosis (MS). NMO differs from MS, however, in the distribution and histology of neuroinflammatory lesions and shows a more aggressive clinical course. Moreover, the majority of NMO patients carry immunoglobulin G autoantibodies against aquaporin-4 ...

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Peripherin-2 is a glycomembrane protein exclusively expressed in the light-sensing compartments of rod and cone photoreceptors designated as outer segments (OS). Mutations in peripherin-2 are associated with degenerative retinal diseases either affecting rod or cone photoreceptors. While peripherin-2 has been extensively studied in rods, there is only little ...

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NMDA receptors, which regulate synaptic strength and are implicated in learning and memory, consist of several subtypes with distinct subunit compositions and functional properties. To enable spatiotemporally defined, rapid and reproducible manipulation of function of specific subtypes, we engineered a set of photoswitchable GluN subunits ('LiGluNs'). ...

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Little is known about how a membrane can regulate interactions between transmembrane helices. Here, we show that strong self-interaction of the transmembrane helix of human quiescin sulfhydryl oxidase 2 rests on a motif of conserved amino acids comprising one face of the helix. Atomistic molecular dynamics simulations suggest that water molecules enter the ...

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During the development of the nematode Caenorhabditis elegans cell death occurs in a highly reproducible manner, and this is one of the reasons why the ‘worm’ has been a prime model for studies of this fundamental process.1 Genetic analyses of C. elegans provided the first evidence that a conserved central pathway of cell death exists and resulted in the ...

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Purpose

Vision originates in rods and cones at the outer retina. Already at these early stages, diverse processing schemes shape and enhance image information to permit perception over a wide range of lighting conditions. In this work, we address the role of hyperpolarization-activated and cyclic nucleotide-gated channels 1 (HCN1) in rod photoreceptors for the ...

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Point mutations in peripherin-2 (PRPH2) are associated with severe retinal degenerative disorders affecting rod and/or cone photoreceptors. Various disease-causing mutations have been identified, but the exact contribution of a given mutation to the clinical phenotype remains unclear. Exonic point mutations are usually assumed to alter single amino acids, thereby ...

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Manipulating the function of neurons and circuits that translate electrical and chemical signals into behavior represents a major challenges in neuroscience. In addition to optogenetic methods using light-activatable channels, pharmacogenetic methods with ligand induced modulation of cell signaling and excitability have been developed. However, they are largely ...

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Most inherited blinding diseases are characterized by compromised retinal function and progressive degeneration of photoreceptors. However, the factors that affect the life span of photoreceptors in such degenerative retinal diseases are rather poorly understood. Here we explore the role of hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1) in ...

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