As an important part of the cytoskeleton, microtubules play a crucial role in many cellular processes, such as cell division, intracellular transport, and maintaining cell morphology. The MAP1 family is an important family of microtubule-associated proteins, which includes three members: MAP1A, MAP1B, and MAP1S. These proteins are widely involved in the dynamic regulation of the cytoskeleton and play a key role in the development and function of the central nervous system, especially in the development and function of neurons. This study reviews the research progress of the MAP1 family, mainly focusing on the structure and function of MAP1 family members, and paying particular attention to their roles in neuronal development and regeneration, regulatory mechanisms, and neurodegenerative diseases.
Humans ; Animals ; Microtubule-Associated Proteins/classification* ; Neurons/cytology* ; Neurodegenerative Diseases/physiopathology* ; Microtubules/physiology* ; Cytoskeleton/physiology*

Leukocyte-specific protein 1 (LSP1) is an F-actin binding protein expressed in various leukocytes, including lymphocytes, mononuclear macrophages, and neutrophils. LSP1 is highly conserved across different species. Human LSP1 protein contains 339 amino acids, featuring a Ca²⁺ binding site in the acidic NH2-terminal region and multiple F-actin binding domains along with phosphorylatable sites in the basic COOH-terminal region. Under Ca²⁺ regulation, the COOH-terminal domain of LSP1 binds to F-actin to regulate cell movement and signal transduction. Additionally, LSP1 activates the mitogen-activated protein kinase (MAPK) signaling pathway through phosphorylation mediated by protein kinase C (PKC) and MAPK-activated protein kinase-2, thereby regulating leukocyte proliferation and chemotaxis. The main effects of LSP1 on leukocytes are as follows: LSP1 plays important roles in neutrophil and macrophage migration, affecting cell adhesion, polarization and movement. LSP1 also functions in endothelial cells to regulate leukocyte transendothelial migration. In addition, LSP1 regulates macrophage phagocytosis through interaction with myosin 1e. Moreover, LSP1 regulates leukocyte proliferation and differentiation and plays significant roles in the development of leukemia and other tumors. In summary, LSP1 regulates leukocyte morphology, movement and function through interactions with cytoskeletal and signaling proteins. This review provides a comprehensive summary of these aspects.
Humans ; Leukocytes/cytology* ; Animals ; Cytoskeleton/metabolism* ; Microfilament Proteins/physiology* ; Cell Movement ; Signal Transduction

The small G-protein Rac1 is the main regulatory factor of the actin cytoskeleton. Rac1 cycles between the inactive GDP-bound form and the active GTP-bound form. Rac1 not only promotes viral replication and infection, but also regulates the actin cytoskeleton rearrangement, adhesion, and invasion of glioma cells. In addition, Rac1 is implicated in human diseases such as tumors and epilepsy. This article reviews the latest research on the small G-protein Rac1 in virology, cell biology, and human pathology. It is found that the existence of Rac1 is closely related to the replication and infection of viruses, that is, inhibiting the existence of Rac1 can effectively reduce the replication and transportation of viruses, providing new ideas for the development of various therapeutic drugs targeting Rac1.
Humans ; rac1 GTP-Binding Protein/genetics* ; Virus Replication ; Glioma/pathology* ; Actin Cytoskeleton/metabolism* ; Animals

As an important intracellular genetic and regulatory center, the nucleus is not only a terminal effector of intracellular biochemical signals, but also has a significant impact on cell function and phenotype through direct or indirect regulation of nuclear mechanistic cues after the cell senses and responds to mechanical stimuli. The nucleus relies on chromatin-nuclear membrane-cytoskeleton infrastructure to couple signal transduction, and responds to these mechanical stimuli in the intracellular and extracellular physical microenvironments. Changes in the morphological structure of the nucleus are the most intuitive manifestation of this mechanical response cascades and are the basis for the direct response of the nucleus to mechanical stimuli. Based on such relationships of the nucleus with cell behavior and phenotype, abnormal nuclear morphological changes are widely used in clinical practice as disease diagnostic tools. This review article highlights the latest advances in how nuclear morphology responds and adapts to mechanical stimuli. Additionally, this article will shed light on the factors that mechanically regulate nuclear morphology as well as the tumor physio-pathological processes involved in nuclear morphology and the underlying mechanobiological mechanisms. It provides new insights into the mechanisms that nuclear mechanics regulates disease development and its use as a potential target for diagnosis and treatment.
Cell Nucleus ; Biophysics ; Cytoskeleton ; Phenotype ; Signal Transduction

Epilepsy is a common, chronic neurological disorder that has been associated with impaired neurodevelopment and immunity. The chemokine receptor CXCR5 is involved in seizures via an unknown mechanism. Here, we first determined the expression pattern and distribution of the CXCR5 gene in the mouse brain during different stages of development and the brain tissue of patients with epilepsy. Subsequently, we found that the knockdown of CXCR5 increased the susceptibility of mice to pentylenetetrazol- and kainic acid-induced seizures, whereas CXCR5 overexpression had the opposite effect. CXCR5 knockdown in mouse embryos via viral vector electrotransfer negatively influenced the motility and multipolar-to-bipolar transition of migratory neurons. Using a human-derived induced an in vitro multipotential stem cell neurodevelopmental model, we determined that CXCR5 regulates neuronal migration and polarization by stabilizing the actin cytoskeleton during various stages of neurodevelopment. Electrophysiological experiments demonstrated that the knockdown of CXCR5 induced neuronal hyperexcitability, resulting in an increased number of seizures. Finally, our results suggested that CXCR5 deficiency triggers seizure-related electrical activity through a previously unknown mechanism, namely, the disruption of neuronal polarity.
Animals ; Humans ; Mice ; Actin Cytoskeleton/metabolism* ; Actins/metabolism* ; Epilepsy/metabolism* ; Neurons/metabolism* ; Receptors, CXCR5/metabolism* ; Seizures/metabolism*

Objective To investigate the effects of lipopolysaccharide (LPS) on human pulmonary vascular endothelial cells (HPVECs) cytoskeleton and perform biological analysis of the microRNA (miRNA) spectrum. Methods The morphology of HPVECs was observed by microscope, the cytoskeleton by FITC-phalloidin staining, and the expression of VE-cadherin was detected by immunofluorescence cytochemical staining; the tube formation assay was conducted to examine the angiogenesis, along with cell migration test to detect the migration, and JC-1 mitochondrial membrane potential to detect the apoptosis. Illumina small-RNA sequencing was used to identify differentially expressed miRNAs in NC and LPS group. The target genes of differentially expressed miRNAs were predicted by miRanda and TargetScan, and the functional and pathway enrichment analysis was performed on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Further biological analysis of related miRNAs was carried out. Results After the LPS got induced, the cells became round and the integrity of cytoskeleton was destroyed. The decreased expression of VE-cadherin was also observed, along with the decreased ability of angiogenesis and migration, and increased apoptosis. Sequencing results showed a total of 229 differential miRNAs, of which 84 miRNA were up-regulated and 145 miRNA were down-regulated. The target gene prediction and functional enrichment analysis of these differential miRNA showed that they were mainly concentrated in pathways related to cell connection and cytoskeleton regulation, cell adhesion process and inflammation. Conclusion In vitro model of lung injury, multiple miRNAs are involved in the process of HPVECs cytoskeleton remodeling, the reduction of barrier function, angiogenesis, migration and apoptosis.
Humans ; Lipopolysaccharides/pharmacology* ; Endothelial Cells/metabolism* ; MicroRNAs/metabolism* ; Lung/metabolism* ; Cytoskeleton ; Gene Expression Profiling

Mice ; Animals ; Actins/metabolism* ; Actin Depolymerizing Factors/metabolism* ; TRPM Cation Channels ; Actin Cytoskeleton/metabolism* ; Nervous System/metabolism*

Microenvironmental biophysical factors play a fundamental role in controlling cell behaviors including cell morphology, proliferation, adhesion and differentiation, and even determining the cell fate. Cells are able to actively sense the surrounding mechanical microenvironment and change their cellular morphology to adapt to it. Although cell morphological changes have been considered to be the first and most important step in the interaction between cells and their mechanical microenvironment, their regulatory network is not completely clear. In the current study, we generated silicon-based elastomer polydimethylsiloxane (PDMS) substrates with stiff (15:1, PDMS elastomer vs. curing agent) and soft (45:1) stiffnesses, which showed the Young's moduli of ~450 kPa and 46 kPa, respectively, and elucidated a new path in cytoskeleton re-organization in chondrocytes in response to changed substrate stiffnesses by characterizing the axis shift from the secreted extracellular protein laminin β1, focal adhesion complex protein FAK to microfilament bundling. We first showed the cellular cytoskeleton changes in chondrocytes by characterizing the cell spreading area and cellular synapses. We then found the changes of secreted extracellular linkage protein, laminin β1, and focal adhesion complex protein, FAK, in chondrocytes in response to different substrate stiffnesses. These two proteins were shown to be directly interacted by Co-IP and colocalization. We next showed that impact of FAK on the cytoskeleton organization by showing the changes of microfilament bundles and found the potential intermediate regulators. Taking together, this modulation axis of laminin β1-FAK-microfilament could enlarge our understanding about the interdependence among mechanosensing, mechanotransduction, and cytoskeleton re-organization.
Cell Adhesion ; Chondrocytes ; Cytoskeleton/metabolism* ; Elastomers/metabolism* ; Laminin/metabolism* ; Mechanotransduction, Cellular

The serine/threonine p21-activated kinases (PAKs), as main effectors of the Rho GTPases Cdc42 and Rac, represent a group of important molecular switches linking the complex cytoskeletal networks to broad neural activity. PAKs show wide expression in the brain, but they differ in specific cell types, brain regions, and developmental stages. PAKs play an essential and differential role in controlling neural cytoskeletal remodeling and are related to the development and fate of neurons as well as the structural and functional plasticity of dendritic spines. PAK-mediated actin signaling and interacting functional networks represent a common pathway frequently affected in multiple neurodevelopmental and neurodegenerative disorders. Considering specific small-molecule agonists and inhibitors for PAKs have been developed in cancer treatment, comprehensive knowledge about the role of PAKs in neural cytoskeletal remodeling will promote our understanding of the complex mechanisms underlying neurological diseases, which may also represent potential therapeutic targets of these diseases.
Animals ; Cytoskeleton/genetics* ; Humans ; Nervous System Diseases/genetics* ; Neurons/enzymology* ; Signal Transduction ; p21-Activated Kinases/metabolism*

OBJECTIVE: To observe the effects of Casitas B lymphoma (CBL) protein on proliferation, migration and invasion of breast cancer cells and explore its mechanism of action. METHODS: Cultured breast cancer cell lines MDA-MB-231 and MCF7A were transfected with a CBL-overexpressing plasmid and a specific siRNA targeting CBL (siRNA-CBL), respectively, and the changes in cell proliferation, migration and invasion were examined using colony-forming assay, cell counting kit-8 (CCK-8), scratch test and Transwell assay. Flow cytometry and Western blotting were performed to examine the effects of CBL overexpression on cell cycle and epithelial-mesenchymal transition (EMT) of MDA-MB-231 cells, and the changes in the number of filamentous pseudopodia were observed by rhodamine- labeled phalloidin staining of the cytoskeleton. IP-mass spectrometry identified NCK2 as the interacting proteins of CBL, and their interaction was verified by immunoprecipitation and immunofluorescence co-localization experiments in HEK-293T cells transfected with the plasmids for overexpression of CBL, NCK2, or both. Cycloheximide tracking and ubiquitination assays were used for assessing the effects of CBL on stability and ubiquitination of NCK2 protein in MDA-MB-231 cells; CCK-8 and Transwell assays were used to determine the effect of NCK2 overexpression on CBL-mediated proliferation and migration of the cells. RESULTS: The proliferation, migration and invasion were significantly suppressed in MDA-MB-231 cells overexpressing CBL (P < 0.05) and significantly enhanced in MCF7 cells with CBL silencing (P < 0.01). Silencing of CBL promoted G1/S transition in MCF7 cells (P < 0.05). Overexpression of CBL significantly decreased the expressions of CDK2/4 (P < 0.01), cyclinA2/B1/D1/D3/E2 (P < 0.05), Snail, N-cadherin, claudin-1 (P < 0.05), and upregulated the expression of E-cadherin (P < 0.05). CBL silencing upregulated the expressions of CDK2/4/6 (P < 0.05), cyclin A2/B1/D1/D3/E2 (P < 0.05), Snail, vimentin, and claudin-1 (P < 0.05) and down-regulated E-cadherin expression (P < 0.05). CBL overexpression obviously reduced the number of filamentous pseudopodia in MDA-MB-231 cells, and the reverse changes were observed in MCF7 cells with CBL silencing. In MDA-MB-231 cells, CBL overexpression lowered NCK2 protein stability (P < 0.05) and promoted its ubiquitin-mediated degradation (P < 0.01). Overexpression of NCK2 obviously reversed CBL-mediated inhibition of cell proliferation and migration (P < 0.01). CONCLUSION CBL can inhibit the proliferation, migration and invasion of breast cancer cells through ubiquitination-mediated degradation of NCK2.
Humans ; Sincalide ; Lymphoma ; Cytoskeleton ; Cadherins ; MCF-7 Cells ; Oncogene Proteins ; Adaptor Proteins, Signal Transducing