Similar Datasets
Project description:Oct4 is arguably a pioneer transcription factor regulating pluripotency. However, it is poorly known whether Oct4 has an impact on somatic cells. We generated OCT4 knockout clonal cell lines using immortalized human skin keratinocytes to identify a functional role for the protein. Here we report that Oct4-deficient cells transitioned into a mesenchymal-like phenotype with enlarged size and shape, exhibited accelerated migratory behavior, decreased adhesion and appeared arrested at G2/M cell cycle checkpoint. Oct4 absence had a profound impact on cortical actin organization, with loss of microfilaments from cell periphery, increased puncta deposition in the cytoplasm and stress fiber formation. E-cadherin, β-catenin and ZO1 were almost absent from cell-cell contacts while fibronectin deposition was markedly increased in ECM. Mapping of the transcriptional and chromatin profiles of Oct4-deficient cells revealed that Oct4 controls the levels of cytoskeletal, ECM and differentiation related genes, whereas epithelial identity is preserved through transcriptional and non-transcriptional mechanisms.
2023-05-09 | GSE230654 | GEO
Project description:Oct4 is arguably a pioneer transcription factor regulating pluripotency. However, it is poorly known whether Oct4 has an impact on somatic cells. We generated OCT4 knockout clonal cell lines using immortalized human skin keratinocytes to identify a functional role for the protein. Here we report that Oct4-deficient cells transitioned into a mesenchymal-like phenotype with enlarged size and shape, exhibited accelerated migratory behavior, decreased adhesion and appeared arrested at G2/M cell cycle checkpoint. Oct4 absence had a profound impact on cortical actin organization, with loss of microfilaments from cell periphery, increased puncta deposition in the cytoplasm and stress fiber formation. E-cadherin, β-catenin and ZO1 were almost absent from cell-cell contacts while fibronectin deposition was markedly increased in ECM. Mapping of the transcriptional and chromatin profiles of Oct4-deficient cells revealed that Oct4 controls the levels of cytoskeletal, ECM and differentiation related genes, whereas epithelial identity is preserved through transcriptional and non-transcriptional mechanisms.
2023-05-09 | GSE230653 | GEO
Project description:Oct4 is a gatekeeper of epithelial identity by regulating cytoskeletal dynamics in skin keratinocytes
| PRJNA962068 | ENA
Project description:Oct4 is a gatekeeper of epithelial identity by regulating cytoskeletal dynamics in skin keratinocytes [ATAC-Seq]
| PRJNA962073 | ENA
Project description:Oct4 is a gatekeeper of epithelial identity by regulating cytoskeletal dynamics in skin keratinocytes [RNA-Seq]
| PRJNA962074 | ENA
Project description:Actomyosin contractility, crucial for several physiological processes including migration, is controlled by the phosphorylation of myosin light chain (MLC). Rho-associated protein kinase (ROCK) and Myosin light chain kinase (MLCK) are predominant kinases that phosphorylate MLC. However, the distinct roles of these kinases in regulating actomyosin contractility and their subsequent impact on the migration of healthy and malignant skin cells is poorly understood. We observed that blockade of ROCK in healthy primary keratinocytes (HPKs) and epidermal carcinoma cell line (A-431 cells) resulted in loss of migration, contractility, focal adhesions, stress fibres, and changes in morphology due to reduction in phosphorylated MLC levels. In contrast, blockade of MLCK reduced migration, contractile dynamics, focal adhesions and phosphorylated MLC levels of HPKs alone and had no effect on A-431 cells due to the negligible MLCK expression. Using genetically modified A-431 cells expressing phosphomimetic mutant of p-MLC, we show that ROCK dependent phosphorylated MLC controls the migration, focal adhesion, stress fibre organization and the morphology of the cells. In conclusion, our data indicate that ROCK is the major kinase of MLC phosphorylation in both HPKs and A-431 cells, and regulates the contractility and migration of healthy as well as malignant skin epithelial cells.
| S-EPMC6934852 | biostudies-literature
Project description:Melanin granules cluster within supra-nuclear caps in basal keratinocytes (KCs) of the human epidermis, where they protect KC genomic DNA against ultraviolet radiation (UVR) damage. While much is known about melanogenesis in melanocytes (MCs) and a moderate amount about melanin transfer from MC to KC, we know little about the fate of melanin once inside KCs. We recently reported that melanin fate in progenitor KCs is regulated by rare asymmetric organelle movement during mitosis. Here, we explore the role of actin, microtubules, and centrosome-associated machinery in distributing melanin within KCs. Short-term cultures of human skin explants were treated with cytochalasin-B and nocodazole to target actin filaments and microtubules, respectively. Treatment effects on melanin distribution were assessed by the Warthin-Starry stain, on centrosome-associated proteins by immunofluorescence microscopy, and on co-localisation with melanin granules by brightfield microscopy. Cytochalasin-B treatment disassembled supra-nuclear melanin caps, while nocodazole treatment moved melanin from the apical to basal KC domain. Centrosome and centriolar satellite-associated proteins showed a high degree of co-localisation with melanin. Thus, once melanin granules are transferred to KCs, their preferred apical distribution appears to be facilitated by coordinated movement of centrosomes and centriolar satellites. This mechanism may control melanin's strategic position within UVR-exposed KCs.
| S-EPMC8003549 | biostudies-literature
Project description:The cytoskeleton has a primary role in cardiomyocyte function, including the response to mechanical stimuli and injury. The small heat shock protein 20 (Hsp20) conveys protective effects in cardiac muscle that are linked to serine-16 (Ser16) Hsp20 phosphorylation by stress-induced PKA, but the link between Hsp20 and the cytoskeleton remains poorly understood. Herein, we demonstrate a physical and functional interaction of Hsp20 with the cytoskeletal protein 14-3-3. We show that, upon phosphorylation at Ser16, Hsp20 translocates from the cytosol to the cytoskeleton where it binds to 14-3-3. This leads to dissociation of 14-3-3 from the F-actin depolymerization regulator cofilin-2 (CFL2) and enhanced F-actin depolymerization. Importantly, we demonstrate that the P20L Hsp20 mutation associated with dilated cardiomyopathy exhibits reduced physical interaction with 14-3-3 due to diminished Ser16 phosphorylation, with subsequent failure to translocate to the cytoskeleton and inability to disassemble the 14-3-3/CFL2 complex. The topological sequestration of Hsp20 P20L ultimately results in impaired regulation of F-actin dynamics, an effect implicated in loss of cytoskeletal integrity and amelioration of the cardioprotective functions of Hsp20. These findings underscore the significance of Hsp20 phosphorylation in the regulation of actin cytoskeleton dynamics, with important implications in cardiac muscle physiology and pathophysiology.
| S-EPMC7765622 | biostudies-literature
Project description:Migration and invasion enhancer 1 (MIEN1) is an important regulator of cell migration and invasion. MIEN1 overexpression represents an oncogenic event that promotes tumor cell dissemination and metastasis. The underlying mechanism by which MIEN1 regulates migration and invasion has yet to be deciphered. Here, we demonstrate that MIEN1 acts as a cytoskeletal-signaling adapter protein to drive breast cancer cell migration. MIEN1 localization is concentrated underneath the actin-enriched protrusive structures of the migrating breast cancer cells. Depletion of MIEN1 led to the loss of actin-protrusive structures whereas the over-expression of MIEN1 resulted in rich and thick membrane extensions. Knockdown of MIEN1 also decreased the cell-substratum adhesion, suggesting a role for MIEN1 in actin cytoskeletal dynamics. Our results show that MIEN1 supports the transition of G-actin to F-actin polymerization and stabilizes F-actin polymers. Additionally, MIEN1 promotes cellular adhesion and actin dynamics by inducing phosphorylation of FAK at Tyr-925 and reducing phosphorylation of cofilin at Ser-3, which results in breast cancer cell migration. Collectively, our data show that MIEN1 plays an essential role in maintaining the plasticity of the dynamic membrane-associated actin cytoskeleton, which leads to an increase in cell motility. Hence, targeting MIEN1 might represent a promising means to prevent breast tumor metastasis.
| S-EPMC5342390 | biostudies-literature
Project description:MicroRNAs (miRNAs) have been implicated in various cellular processes, such as cell fate determination, cell death, and tumorigenesis. In the present study, we investigated the role of miRNA-34a (miR-34a) in the reorganization of the actin cytoskeleton, which is essential for chondrocyte differentiation. miRNA arrays to identify genes that appeared to be up-regulated or down-regulated during chondrogenesis were applied with chondrogenic progenitors treated with JNK inhibitor. PNA-based antisense oligonucleotides and miRNA precursor were used for investigation of the functional roles of miR-34a. We found that, in chick chondroprogenitors treated with JNK inhibitor, which suppresses chondrogenic differentiation, the expression levels of miR-34a and RhoA1 are up-regulated through modulation of Rac1 expression. Blockade of miR-34a via the use of PNA-based antisense oligonucleotides was associated with decreased protein expression of RhoA (a known modulator of stress fiber expression), down-regulation of stress fibers, up-regulation of Rac1, and recovery of protein level of type II collagen. miR-34a regulates RhoA/Rac1 cross-talk and negatively modulates reorganization of the actin cytoskeleton, which is one of the essential processes for establishing chondrocyte-specific morphology.
| S-EPMC3320999 | biostudies-literature