NCBI Summary:
Dynamins represent one of the subfamilies of GTP-binding proteins. These proteins share considerable sequence similarity over the N-terminal portion of the molecule, which contains the GTPase domain. Dynamins are associated with microtubules. They have been implicated in cell processes such as endocytosis and cell motility, and in alterations of the membrane that accompany certain activities such as bone resorption by osteoclasts. Dynamins bind many proteins that bind actin and other cytoskeletal proteins. Dynamins can also self-assemble, a process that stimulates GTPase activity. Five alternatively spliced transcripts encoding different proteins have been described. Additional alternatively spliced transcripts may exist, but their full-length nature has not been determined. [provided by RefSeq, Jun 2010]
Involvement of Dynamin 2 in actin-based polar-body extrusion during porcine oocyte maturation. Zhang Y 2014 et al.
Mammalian oocyte meiotic maturation involves a unique asymmetric division, but the regulatory mechanisms and signaling pathways involved are poorly understood. Dynamins are ubiquitous eukaryotic GTPases involved in membrane trafficking and actin dynamics, whose roles in mammalian oocyte maturation have not been determined. In this study, we used porcine oocytes to show that Dynamin 2 accumulated at the meiotic spindle and in the cortex of oocytes, with a distribution similar to that of actin. Inhibiting Dynamin 2 activity in porcine oocytes with the specific inhibitor dynasore resulted in failed polar-body extrusion. This phenotype may have been due to aberrant actin distribution and/or spindle positioning as inhibitor treatment disrupted the formation of the actin cap and cortical granule-free domain, which negatively impacted spindle positioning. Moreover, the distribution of ARP2, a key actin-nucleation factor, was severely reduced in the cortex after dynasore treatment. Thus, our results suggest that Dynamin 2 possibly regulates porcine oocyte maturation through its effects on actin-mediated spindle positioning and cytokinesis, and that this may depend on regulating ARP2 localization. Mol. Reprod. Dev. 2014 Wiley Periodicals, Inc.
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Follicle stages
Comment
Phenotypes
Mutations
1 mutations
Species: mouse
Mutation name: type: null mutation fertility: infertile - ovarian defect Comment: Dynamin 2-dependent endocytosis is essential for mouse oocyte development and fertility. Mihalas BP et al. (2020) During folliculogenesis, oocytes are dependent on metabolic and molecular support from surrounding somatic cells. Here, we examined the role of the dynamin (DNM) family of mechanoenzymes in mediating endocytotic uptake into growing follicular oocytes. We found DNM1 and DNM2 to be highly expressed in growing follicular oocytes as well as in mature germinal vesicle (GV) and metaphase II (MII) stage oocytes. Moreover, oocyte-specific conditional knockout (cKO) of DNM2 (DNM2Δ) led to complete sterility, with follicles arresting at the preantral stage of development. In addition, DNM2Δ ovaries were characterized by disrupted follicular growth as well as oocyte and follicle apoptosis. Further, the loss of DNM activity, either through DNM2 cKO or through pharmacological inhibition (Dyngo 6a) led to the impairment of endocytotic pathways in preantral oocytes as well as in mature GV and MII oocytes, respectively. Loss of DNM activity resulted in the redistribution of endosomes and the misslocalization of clathrin and actin, suggesting dysfunctional endocytosis. Notably, there was no observable effect on the fertility of DNM1Δ females. Our study has provided new insight into the complex and dynamic nature of oocyte growth during folliculogenesis, suggesting a role for DNM2 in mediating the endocytotic events that are essential for oocyte development.//////////////////