|
General Comment |
Kureishy N, et al 2002 reviewed fascins, and their roles in cell structure and function.
The fascins are a structurally unique and evolutionarily conserved group of
actin cross-linking proteins. Fascins function in the organisation of two
major forms of actin-based structures: dynamic, cortical cell protrusions and
cytoplasmic microfilament bundles. The cortical structures, which include
filopodia, spikes, lamellipodial ribs, oocyte microvilli and the dendrites of
dendritic cells, have roles in cell-matrix adhesion, cell interactions and
cell migration, whereas the cytoplasmic actin bundles appear to participate in
cell architecture.
NCBI Summary:
This gene encodes a member of the fascin family of actin-binding proteins. Fascin proteins organize F-actin into parallel bundles, and are required for the formation of actin-based cellular protrusions. The encoded protein plays a critical role in cell migration, motility, adhesion and cellular interactions. Expression of this gene is known to be regulated by several microRNAs, and overexpression of this gene may play a role in the metastasis of multiple types of cancer by increasing cell motility. Expression of this gene is also a marker for Reed-Sternberg cells in Hodgkin's lymphoma. A pseudogene of this gene is located on the long arm of chromosome 15. [provided by RefSeq, Sep 2011]
|
|
Comment |
FASCIN regulates actin assembly for spindle movement and polar body extrusion in mouse oocyte meiosis. Hu LL et al. (2021) During mouse oocyte meiotic maturation, actin filaments play multiple roles in meiosis such as spindle migration and cytokinesis. FASCIN is shown to be an actin-binding and bundling protein, making actin filaments tightly packed and parallel-aligned, and FASCIN is involved in several cellular processes like adhesion and migration. FASCIN is also a potential prognostic biomarker and therapeutic target for the treatment of metastatic disease. However, little is known about the functions of FASCIN in oocyte meiosis. In the present study, we knocked down the expression of FASCIN, and our results showed that FASCIN was essential for oocyte maturation. FASCIN was all expressed in the different stages of oocyte meiosis, and it mainly localized at the cortex of oocytes from the GV stage to the MII stage and showed a similar localization pattern with actin and DAAM1. Depletion of FASCIN affected the extrusion of the first polar body, and we also observed that some oocytes extruded from the large polar bodies. This might have resulted from the defects of actin assembly, which further affected the meiotic spindle positioning. In addition, we showed that inhibition of PKC activity decreased FASCIN expression, indicating that FASCIN might be regulated by PKC. Taken together, our results provided evidence for the important role of FASCIN on actin filaments for spindle migration and polar body extrusion in mouse oocyte meiosis.//////////////////FMNL3 regulates FASCIN for actin-mediated spindle migration and cytokinesis in mouse oocytes. Pan MH et al. (2020) Formin-like 3 (FMNL3) is a member of the formin-likes (FMNLs), which belong to the formin family. As an F-actin nucleator, FMNL3 is essential for several cellular functions, such as polarity control, invasion, and migration. However, the roles of FMNL3 during oocytes meiosis remain unclear. In this study, we investigated the functions of FMNL3 during mouse oocyte maturation. Our results showed that FMNL3 mainly concentrated in the oocyte cortex and spindle periphery. Depleting FMNL3 led to the failure of polar body extrusion, and we also found large polar bodies in the FMNL3-deleted oocytes, indicating the occurrence of symmetric meiotic division. There was no effect of FMNL3 on spindle organization; however, we observed spindle migration defects at late metaphase I, which might be due to the decreased cytoplasmic actin. Microinjecting Fmnl3-EGFP mRNA into Fmnl3-depleted oocytes significantly rescued these defects. In addition, the results of co-immunoprecipitation and the perturbation of protein expression experiments suggested that FMNL3 interacted with the actin-binding protein FASCIN for the regulation of actin filaments in oocytes. Thus, our results provide the evidence that FMNL3 regulates FASCIN for actin-mediated spindle migration and cytokinesis during mouse oocyte meiosis.//////////////////
Fascin regulates nuclear actin during Drosophila oogenesis. Kelpsch DJ et al. (2016) Drosophila oogenesis provides a developmental system to study nuclear actin. During Stages 5-9, nuclear actin levels are high in the oocyte and exhibit variation within the nurse cells. Cofilin and Profilin, which regulate the nuclear import and export of actin, also localize to the nuclei. Expression of GFP-tagged Actin results in nuclear actin rod formation. These findings indicate that nuclear actin must be tightly regulated during oogenesis. One factor mediating this regulation is Fascin. Overexpression of Fascin enhances nuclear GFP-Actin rod formation, and Fascin colocalizes with the rods. Loss of Fascin reduces, while overexpression of Fascin increases, the frequency of nurse cells with high levels of nuclear actin; but neither alters the overall nuclear level of actin within the ovary. These data suggest that Fascin regulates the ability of specific cells to accumulate nuclear actin. Evidence indicates Fascin positively regulates nuclear actin through Cofilin. Loss of Fascin results in decreased nuclear Cofilin. Additionally, Fascin and Cofilin genetically interact, as double heterozygotes exhibit a reduction in the number of nurse cells with high nuclear actin levels. These findings are likely applicable beyond Drosophila follicle development, as the localization and functions of Fascin, and the mechanisms regulating nuclear actin, are widely conserved.//////////////////
|