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RIC8 guanine nucleotide exchange factor A OKDB#: 5199
 Symbols: RIC8A Species: human
 Synonyms: RIC8  Locus: 11p15.5 in Homo sapiens


For retrieval of Nucleotide and Amino Acid sequences please go to: OMIM Entrez Gene
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General Comment
General function Intracellular signaling cascade
Comment
Cellular localization Cytoplasmic
Comment
Ovarian function
Comment
Expression regulated by
Comment
Ovarian localization Oocyte
Comment Expression Pattern and Localization Dynamics of Guanine Nucleotide Exchange Factor RIC8 during Mouse Oogenesis. Saare M et al. (2015) Targeting of G proteins to the cell cortex and their activation is one of the triggers of both asymmetric and symmetric cell division. Resistance to inhibitors of cholinesterase 8 (RIC8), a guanine nucleotide exchange factor, activates a certain subgroup of G protein α-subunits in a receptor independent manner. RIC8 controls the asymmetric cell division in Caenorhabditis elegans and Drosophila melanogaster, and symmetric cell division in cultured mammalian cells, where it regulates the mitotic spindle orientation. Although intensely studied in mitosis, the function of RIC8 in mammalian meiosis has remained unknown. Here we demonstrate that the expression and subcellular localization of RIC8 changes profoundly during mouse oogenesis. Immunofluorescence studies revealed that RIC8 expression is dependent on oocyte growth and cell cycle phase. During oocyte growth, RIC8 is abundantly present in cytoplasm of oocytes at primordial, primary and secondary preantral follicle stages. Later, upon oocyte maturation RIC8 also populates the germinal vesicle, its localization becomes cell cycle dependent, and it associates with chromatin and the meiotic spindle. After fertilization, RIC8 protein converges to the pronuclei and is also detectable at high levels in the nucleolus precursor bodies of both maternal and paternal pronucleus. During first cleavage of zygote RIC8 localizes in the mitotic spindle and cell cortex of forming blastomeres. In addition, we demonstrate that RIC8 co-localizes with its interaction partners Gαi1/2:GDP and LGN in meiotic/mitotic spindle, cell cortex and polar bodies of maturing oocytes and zygotes. Downregulation of Ric8 by siRNA leads to interferred translocation of Gαi1/2 to cortical region of maturing oocytes and reduction of its levels. RIC8 is also expressed at high level in female reproductive organs e.g. oviduct. Therefore we suggest a regulatory function for RIC8 in mammalian gametogenesis and fertility.//////////////////
Follicle stages Primordial, Primary, Secondary, Antral, Preovulatory
Comment
Phenotypes
Mutations 0 mutations
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Phenotypes and GWAS show phenotypes and GWAS
Links
OMIM (Online Mendelian Inheritance in Man: an excellent source of general gene description and genetic information.)
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created: June 12, 2015, 2:35 p.m. by: system   email:
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last update: June 12, 2015, 2:38 p.m. by: hsueh    email:



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