Tubulin x plectin

Understanding the basic solubilization of fish myofibrillar proteins (MPs) in common monovalent chloride solutions is crucial for muscle food processing. In this study, the differential proteomic profiles of MPs during extraction and solubilization in NaCl and KCl solutions were investigated by using advanced four-dimensional data-independent acquisition (4D DIA) quantitative proteomics for the first time. Compared to routine biochemical analysis, this could provide insights into the solubilization of muscle proteins. We ensure the consistency of the effective ionic strength of NaCl and KCl buffers by adjusting the conductivity. The results showed that NaCl extractor mainly facilitated the solubilization of cytoskeletal proteins, biochemical enzymes, and stromal proteins compared to KCl, such as tubulin, myosin-9, collagen, plectin, protein phosphatase, and cathepsin D. However, no significant difference was observed in the extraction of major sarcomeric proteins, including myosin, actin, troponin C, myosin-binding protein C, M-Protein, α-actinin-3, and tropomyosin.

Alveolar epithelial barrier integrity is essential for lung homeostasis. Na, K-ATPase β1 subunit (ATP1B1) involves alveolar edema fluid clearance and alveolar epithelial barrier stability. However, the underlying molecular mechanism of ATP1B1 in alveolar epithelial cells still needs to be understood.

We utilized Co-Immunoprecipitation mass spectrometry proteomic analysis, protein-protein interaction (PPI) analysis, enrichment analysis, and parallel reaction monitoring (PRM) analysis to investigate proteins interacting with ATP1B1 in A549 cells.

A total of 159 proteins were identified as significant proteins interacting with ATP1B1 in A549 cells. Ribosomal and heat shock proteins were major constituents of the two main functional modules based on the PPI network. Enrichment analysis showed that significant proteins were involved in protein translation, posttranslational processing, and function regulation. Moreover, 10 proteins of interest were verified by PRM, and fold changes in 6 proteins were consistent with proteomics results. Finally, HSP90AB1, EIF4A1, TUBB4B, HSPA8, STAT1, and PLEC were considered candidates for binding to ATP1B1 to function in alveolar epithelial cells.

Our study provides new insights into the role of ATP1B1 in alveolar epithelial cells and indicates that six proteins, in particular HSP90AB1, may be key proteins interacting with and regulating ATP1B1, which might be potential targets for the treatment of acute respiratory distress syndrome.

Plectin, a universally expressed multi‐functional cytolinker protein, is crucial for intermediate filament networking, including crosstalk with actomyosin and microtubules. In addition to its involvement in a number of diseases affecting skin, skeletal muscle, heart, and other stress‐exposed tissues, indications for a neuropathological role of plectin have emerged. Having identified P1c as the major isoform expressed in neural tissues in previous studies, our aim for the present work was to investigate whether, and by which mechanism(s), the targeted deletion of this isoform affects neuritogenesis and proper nerve cell functioning.

For ex vivo phenotyping, we used dorsal root ganglion and hippocampal neurons derived from isoform P1c‐deficient and plectin‐null mice, complemented by in vitro experiments using purified proteins and cell fractions. To assess the physiological significance of the phenotypic alterations observed in P1c‐deficient neurons, P1c‐deficient and wild‐type littermate mice were subjected to standard behavioural tests.

We demonstrate that P1c affects axonal microtubule dynamics by isoform‐specific interaction with tubulin. P1c deficiency in neurons leads to altered dynamics of microtubules and excessive association with tau protein, affecting neuritogenesis, neurite branching, growth cone morphology, and translocation and directionality of movement of vesicles and mitochondria. On the organismal level, we found P1c deficiency manifesting as impaired pain sensitivity, diminished learning capabilities and reduced long‐term memory of mice.

Revealing a regulatory role of plectin scaffolds in microtubule‐dependent nerve cell functions, our results have potential implications for cytoskeleton‐related neuropathies.