Biology subjects

Proszynski, T. J.

Publications and source records attributed to Proszynski, T. J..

4 recordsLinked to original sources

bioRxiv2024

SH3BP2 regulates the organization of the neuromuscular synapses through protein-driven phase separation

The molecular mechanisms underlying the development and maintenance of the neuromuscular junction are poorly understood, even though the malfunction of these specialized synapses is associated with severe genetic and autoimmune disorders. The identity of factors controlling the maintenance mechanisms of postsynaptic acetylcholine receptors (AChR) in high-density has been elusive and is of great interest to the pharma industry, searching for possible new targets for disease interventions. Here, we report the identification of a scaffold protein SH3BP2, which exhibits polyvalent interaction with the dystrophin-glycoprotein complex (DGC) and AChR pentamers, promoting AChR clustering through phase separation. Muscle-specific SH3BP2 deletion in mice leads to impaired organization of the neuromuscular synapses, defects in synaptic transmission, and reduced muscle strength. Our studies identified a novel regulator of the postsynaptic machinery involved in clustering AChR and linking it to the DGC.

neuroscience↗

bioRxiv2020

Lynx1 modulates the activity of nAChRs to slow NMJ and muscle fiber degeneration during aging

The authors have withdrawn their manuscript to revisit some of the data, interpretations and conclusions. Therefore, the authors do not wish this work to be cited as a reference. If you have any questions, please contact the corresponding author.

neuroscience↗

bioRxiv2019

An improved method for culturing myotubes on laminins for the robust clustering of postsynaptic machinery

Motor neurons form specialized synapses with skeletal muscle fibers, called neuromuscular junctions (NMJs). Cultured myotubes are used as a simplified in vitro system to study the postsynaptic specialization of muscles. The stimulation of myotubes with the glycoprotein agrin or laminin-111 induces the clustering of postsynaptic machinery that contains acetylcholine receptors (AChRs). When myotubes are grown on laminin-coated surfaces, AChR clusters undergo developmental remodeling to form topologically complex structures that resemble mature NMJs. Needing further exploration are the molecular processes that govern AChR cluster assembly and its developmental maturation. Here, we describe an improved protocol for culturing muscle cells to promote the formation of complex AChR clusters. We screened various laminin isoforms and showed that laminin-221 was the most potent for inducing AChR clusters, whereas laminin-121, laminin-211, and laminin-221 afforded the highest percentages of topologically complex assemblies. Human primary myotubes that were formed by myoblasts obtained from patient biopsies also assembled AChR clusters that underwent remodeling in vitro. Collectively, these results demonstrate an advancement of culturing myotubes that can facilitate high-throughput screening for potential therapeutic targets for neuromuscular disorders.

cell biology↗

bioRxiv2018

Amot regulates neuronal dendritic tree through Yap1

The Amot-Yap1 complex plays a major role in the regulation of cell contact inhibition, cellular polarity and growth. However, the function of Angiomotin (Amot) and Hippo pathway transcription co-activator Yap1 in the central nervous system remains unclear. In this study, we demonstrate that Amot is a critical mediator of dendritic morphogenesis in cultured hippocampal cells and Purkinje cells in the brain. Amot function in developing hippocampal neurons depends on interactions with Yap1, which is also indispensable for dendrite growth and arborization in vitro. Conditional deletion of Amot or Yap1 in neurons leads to impaired morphogenesis of Purkinje cell dendritic trees, decreased cerebellar size, and causes defects in locomotor coordination of mutant animals. Thus, our studies identified Amot and Yap1 as novel regulators of dendritic tree morphogenesis.

neuroscience↗