Biology subjects

Manning, D.

Publications and source records attributed to Manning, D..

3 recordsLinked to original sources

bioRxiv2026

Intracellular Mechanosensation in Intestinal Smooth Muscle: Piezo1 Complexes Amplify Signaling Beyond the Surface

Mechanosensation is fundamentally viewed as a plasma membrane phenomenon. We challenge this paradigm by introducing intracellular mechanosensation in intestinal smooth muscle. We hypothesized that a distinct, organelle-based signaling axis exists to amplify mechanotransduction from the inside out. To test this, we investigated whether Piezo1, a canonical plasma membrane mechanosensor, also operates within the cell. Using tissue-level wire myography, high-resolution confocal microscopy, proximity ligation assays, and patch-clamp electrophysiology on freshly dissociated cells, we identified a functional intracellular signaling hub that starts at the sarcoplasmic reticulum (SR). Unlike surface transduction, this intracellular mechanism relies on a nanoscale multiprotein complex (<40 nm) comprising an SR sensor (intra-Piezo1) and an amplifier (Ryanodine Receptor, RyR), coupled with a PM effector (large-conductance, Ca2+-activated K+ channels, i.e., BKCa channels). Activating this intracellular complex generated massive BK-mediated outward currents independent of extracellular Ca{superscript 2} but strictly dependent on internal SR Ca{superscript 2} stores, confirming intrinsic organellar mechanotransduction. Within this complex, intra-Piezo1 and RyR are positioned to operate as a coupled SR Ca{superscript 2} release unit that activates BK channels at SR-PM junctions, driving potent membrane hyperpolarization that reduces smooth muscle contractility, revealing the intra-Piezo1 complex as a molecular brake on excitation. These findings demonstrate that mechanotransduction is not confined to the cell surface. Instead, a specialized Sensor-Amplifier-Effector complex originating at intracellular organelles amplifies cellular sensitivity to physical force, providing a critical gain-control system that restrains smooth muscle excitability and regulates GI motility. Key PointsO_LIIntracellular organelles contribute to mechanosensory signaling in GI smooth muscle cells, complementing plasma membrane mechanisms. C_LIO_LIIntra-Piezo1 form a nanoscale signaling complex (<40nm) on the sarcoplasmic reticulum (SR), linking the mechanosensor Piezo1 with RyR and large conductance, Ca2+-activated K+ channels. C_LIO_LIUnlike surface sensors, this intracellular complex functions via a "Sensor-Amplifier-Effector" mechanism in which intra-Piezo1 detects mechanical stress and triggers SR Ca2+ release, thereby activating a nearby RyR and large-conductance, Ca2+-activated K+ channel. C_LIO_LIEngaging this intracellular Piezo1-mediated axis significantly dampens smooth muscle contractility, identifying a critical gain-control system essential for regulating GI motility. C_LI

physiology↗

bioRxiv2023

The formation of KV2.1 macro-clusters is required for sex-specific differences in L-type CaV1.2 clustering and function in arterial myocytes

In arterial myocytes, the canonical function of voltage-gated CaV1.2 and KV2.1 channels is to induce myocyte contraction and relaxation through their responses to membrane depolarization, respectively. Paradoxically, KV2.1 also plays a sex-specific role by promoting the clustering and activity of CaV1.2 channels. However, the impact of KV2.1 protein organization on CaV1.2 function remains poorly understood. We discovered that KV2.1 forms micro-clusters, which can transform into large macro-clusters when a critical clustering site (S590) in the channel is phosphorylated in arterial myocytes. Notably, female myocytes exhibit greater phosphorylation of S590, and macro-cluster formation compared to males. Contrary to current models, the activity of KV2.1 channels seems unrelated to density or macro-clustering in arterial myocytes. Disrupting the KV2.1 clustering site (KV2.1S590A) eliminated KV2.1 macro-clustering and sex-specific differences in CaV1.2 cluster size and activity. We propose that the degree of KV2.1 clustering tunes CaV1.2 channel function in a sex-specific manner in arterial myocytes.

physiology↗

bioRxiv2021

The 22q11.2 region regulates presynaptic gene-products linked to schizophrenia

To study how the 22q11.2 deletion predisposes to psychiatric disease, we generated induced pluripotent stem cells from deletion carriers and controls, as well as utilized CRISPR/Cas9 to introduce the heterozygous deletion into a control cell line. Upon differentiation into neural progenitor cells, we found the deletion acted in trans to alter the abundance of transcripts associated with risk for neurodevelopmental disorders including Autism Spectrum Disorder. In more differentiated excitatory neurons, altered transcripts encoded presynaptic factors and were associated with genetic risk for schizophrenia, including common (per-SNP heritability p ({tau}c)= 4.2 x 10-6) and rare, loss of function variants (p = 1.29x10-12). These findings suggest a potential relationship between cellular states, developmental windows and susceptibility to psychiatric conditions with different ages of onset. To understand how the deletion contributed to these observed changes in gene expression, we developed and applied PPItools, which identifies the minimal protein-protein interaction network that best explains an observed set of gene expression alterations. We found that many of the genes in the 22q11.2 interval interact in presynaptic, proteasome, and JUN/FOS transcriptional pathways that underlie the broader alterations in psychiatric risk gene expression we identified. Our findings suggest that the 22q11.2 deletion impacts genes and pathways that may converge with risk loci implicated by psychiatric genetic studies to influence disease manifestation in each deletion carrier.

neuroscience↗