Biology subjects

Goehring, A.

Publications and source records attributed to Goehring, A..

6 recordsLinked to original sources

bioRxiv2026

AMPAR immunization induces progressive autoimmune encephalitis with autoreactive B cells in the brain

AMPA and NMDA receptors are central to synaptic plasticity and cognitive function. In anti-NMDA receptor and anti-AMPA receptor (AMPAR) encephalitis, autoantibodies targeting these receptors disrupt synaptic signaling, leading to severe neuropsychiatric symptoms. However, the cellular autoimmune responses and source of pathogenic autoantibodies during onset and progression of central nervous system (CNS) pathology remain poorly understood. By immunizing mice with intact AMPARs in proteoliposomes, we developed a mouse model of anti-AMPAR encephalitis. Mice developed rapidly progressing neuropsychiatric deficits, autoantibodies targeting the AMPAR amino-terminal domain (ATD) and IgG deposition in the brain, accompanied by reduced AMPAR detection. Throughout disease onset and progression, AMPAR-ATD-specific non-proliferating plasma cells and plasmablasts accumulated in the brain and were predominantly localized in AMPAR-expressing brain parenchyma. In contrast, differentiated AMPAR-ATD specific B cells were far less enriched in peripheral lymphoid tissues. Our results suggest that humoral autoimmune responses directly in the CNS drives disease progression in anti-AMPAR encephalitis.

neuroscience↗

bioRxiv2023

Single molecule studies of the native hair cell mechanosensory transduction complex

Hearing and balance rely on the conversion of a mechanical stimulus into an electrical signal, a process known as mechanosensory transduction (MT). In vertebrates, this process is accomplished by an MT complex that is located in hair cells of the inner ear. While the past three decades of research have identified many subunits that are important for MT and revealed interactions between these subunits, the composition and organization of a functional complex remains unknown. The major challenge associated with studying the MT complex is its extremely low abundance in hair cells; current estimates of MT complex quantity range from 3-60 attomoles per cochlea or utricle, well below the detection limit of most biochemical assays that are used to characterize macromolecular complexes. Here we describe the optimization of two single molecule assays, single molecule pull-down (SiMPull) and single molecule array (SiMoA), to study the composition and quantity of native mouse MT complexes. We demonstrate that these assays are capable of detecting and quantifying low attomoles of the native MT subunits protocadherin-15 (PCDH15) and lipoma HMGIC fusion partner-like protein 5 (LHFPL5). Our results illuminate the stoichiometry of PCDH15- and LHFPL5-containing complexes and establish SiMPull and SiMoA as productive methods for probing the abundance, composition, and arrangement of subunits in the native MT complex. Impact StatementIn the present work, the authors develop and employ single molecule methods to detect, characterize, and quantitate attomole quantities of the hair cell mechanosensory transduction complex.

biochemistry↗

bioRxiv2023

Structure of C. elegans TMC-2 complex suggests roles of lipid-mediated subunit contacts in mechanosensory transduction

Mechanotransduction is the process by which a mechanical force, such as touch, is converted into an electrical signal. Transmembrane channel-like (TMC) proteins are an evolutionarily-conserved family of ion channels whose function has been linked to a variety of mechanosensory processes, including hearing and balance sensation in vertebrates and locomotion in Drosophila. The molecular features that tune homologous TMC ion channel complexes to diverse mechanical stimuli are unknown. Caenorhabditis elegans express two TMC homologs, TMC-1 and TMC-2, both of which are the likely pore-forming subunits of mechanosensitive ion channels but differ in their expression pattern and functional role in the worm. Here we present the single particle cryo-electron microscopy structure of the native TMC-2 complex isolated from C. elegans. The complex is composed of two copies each of the pore-forming TMC-2 subunit, the calcium and integrin binding protein CALM-1 and the transmembrane inner ear protein TMIE. Comparison of the TMC-2 complex to the recently published cryo-EM structure of the C. elegans TMC-1 complex reveals differences in subunit composition and highlights conserved protein-lipid interactions, as well as other structural features, that together suggest a mechanism for TMC-mediated mechanosensory transduction. Significance StatementOne mechanism by which organisms sense their environment is through the perception of mechanical stimuli such as sound, touch, and vibration. Transmembrane channel-like (TMC) proteins are ion channels whose function has been linked to a variety of mechanosensitive processes, including hearing and balance in vertebrates and touch sensation in worms. The molecular mechanisms by which TMCs respond to mechanical stimuli are unknown. Here we present the structure of the TMC-2 complex isolated from worms. Comparison of the TMC-2 complex to the recently solved structure of the worm TMC-1 complex highlights common structural features that are likely important for sensing mechanical stimuli yet also illuminates key differences that may explain the distinct functional roles of TMC-1 and TMC-2 in the worm.

biochemistry↗

bioRxiv2022

Structure of C. elegans TMC-1 complex illuminates auditory mechanosensory transduction

The initial step in the sensory transduction pathway underpinning hearing and balance in mammals involves the conversion of force into the gating of a mechanosensory transduction (MT) channel. Despite the profound socioeconomic impacts of hearing disorders and the fundamental biological significance of understanding MT, the composition, structure and mechanism of the MT complex has remained elusive. Here we report the single particle cryo-EM structure of the native MT TMC-1 complex isolated from C. elegans. The 2-fold symmetric complex is composed of 2 copies each of the pore-forming TMC-1 subunit, the calcium-binding protein CALM-1 and the transmembrane inner ear protein TMIE. CALM-1 makes extensive contacts with the cytoplasmic face of the TMC-1 subunits while the single-pass TMIE subunits reside on the periphery of the complex, poised like the handles of an accordion. A subset of particles in addition harbors a single arrestin-like protein, ARRD-6, bound to a CALM-1 domain. Single- particle reconstructions and molecular dynamics simulations show how the MT complex deforms the membrane bilayer and suggest crucial roles for lipid-protein interactions in the mechanism by which mechanical force is transduced to ion channel gating.

biochemistry↗

bioRxiv2021

Molecular structure and conformation of stereocilia tip-links elucidated by cryo-electron tomography

Mechanosensory transduction (MT), the conversion of mechanical stimuli into electrical signals, underpins hearing and balance and is carried out within hair cells in the inner ear. Hair cells harbor actin-filled stereocilia, arranged in rows of descending heights, where the tips of stereocilia are connected to their taller neighbors by a filament composed of protocadherin 15 (PCDH15) and cadherin 23 (CDH23), deemed the tip-link. Tension exerted on the tip-link opens an ion channel at the tip of the shorter stereocilia, thus converting mechanical force into an electrical signal. While biochemical and structural studies have provided insights into the molecular composition and structure of isolated portions of the tip-link, the architecture, location and conformational states of intact tip-links, on stereocilia, remains unknown. Here we report in situ cryo-electron microscopy imaging of the tip-link in mouse stereocilia. We observe individual PCDH15 molecules at the tip and shaft of stereocilia and determine their stoichiometry, conformational heterogeneity, and their complexes with CDH23. The PCDH15/CDH23 complexes occur in clusters, frequently with more than one copy of PCDH15 at the tip of stereocilia, suggesting that tip-links might consist of more than one copy of the PCDH15/CDH23 heterotetramer and by extension, might include multiple MT complexes.

neuroscience↗

bioRxiv2018

Anti-NMDA receptor encephalitis in mice induced by active immunization with conformationally-stabilized holoreceptors

Autoimmunity to membrane proteins in the central nervous system has been increasingly recognized as a cause of neuropsychiatric disease. A key recent development was the discovery of antibodies to NMDA receptors in limbic encephalitis, characterized by cognitive changes, memory loss, seizures and sometimes long-term morbidity or mortality. Treatment approaches and experimental studies have largely focused on the pathogenic role of these autoantibodies. Passive antibody transfer to mice has provided useful insights, but does not produce the full spectrum of the human disease. Here we describe a de novo autoimmune mouse model of anti-NMDA receptor encephalitis. Active immunization of immune competent mice with conformationally-stabilized, native-like NMDA receptors induced a fulminant encephalitis that was strikingly similar to the behavioral and pathologic characteristics of human cases. Our results provide evidence of neuroinflammation and immune cell infiltration as early and robust features of the autoimmune response. Use of transgenic mice indicated that mature T cells as well as antibody-producing cells were required for disease induction. Our results provide new insights into disease pathogenesis as well as a platform for testing mechanisms of disease initiation and therapeutic approaches.\n\nOne Sentence SummaryWe report an active immunization model of anti-NMDA receptor encephalitis in mice that recapitulates the features of the clinical disease, provides new insights into the pathophysiology, and offers a platform for investigation of new therapeutic interventions.

neuroscience↗