NCBI Summary:
Peptidyl-prolyl cis/trans isomerases (PPIases) catalyze the cis/trans isomerization of peptidyl-prolyl peptide bonds. This gene encodes one of the PPIases, which specifically binds to phosphorylated ser/thr-pro motifs to catalytically regulate the post-phosphorylation conformation of its substrates. The conformational regulation catalyzed by this PPIase has a profound impact on key proteins involved in the regulation of cell growth, genotoxic and other stress responses, the immune response, induction and maintenance of pluripotency, germ cell development, neuronal differentiation, and survival. This enzyme also plays a key role in the pathogenesis of Alzheimer's disease and many cancers. Multiple alternatively spliced transcript variants have been found for this gene.[provided by RefSeq, Jun 2011]
General function
Enzyme
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Cellular localization
Cytoplasmic
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Ovarian function
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Expression regulated by
FSH, LH
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Expression of Pin1, A Peptidyl-Prolyl Isomerase, in the Ovaries of eCG/hCG-treated Immature Female Mice Shimizu T, et al .
Protein phosphorylation on certain serine or threonine residues preceding proline (Ser/Thr-Pro) is a pivotal signaling mechanism in diverse cellular processes. Pin1 is a highly conserved enzyme that isomerizes only the phosphorylated Ser/Thr-Pro bonds in certain proteins, thereby inducing conformational changes. Although much protein is phosphorylated in the ovary, the role of Pin1 in the ovary is still unknown. The purpose of this study is to investigate the effects of gonadotropins on protein and mRNA expression of Pin1 in mice ovaries. Quantitative PCR analysis showed that the expression of Pin1 mRNA significantly increased in the ovaries of equine chorionic gonadotropin (eCG)-treated mice compared with those of untreated mice (P<0.05). However, human chorionic gonadotropin (hCG) attenuated the expression of Pin1 mRNA increased by eCG. The protein level of Pin1 showed the same tendency as the expression of mRNA. The mRNA expression of E2F transcription factor, which controlled the expression of Pin1, was significantly decreased in the eCG-treated ovaries compared with the controls (P<0.05). These observations suggest that gonadotropins may regulate the expression of Pin1 without E2F transcription factor, indicating that Pin1 might be an important factor for protein signal transduction during follicular development.
Follicle-stimulating hormone (FSH) stimulates the expression of Pin1, a peptidyl-prolyl isomerase, in the bovine granulosa cells. Shimizu T et al. A peptidyl-prolyl isomerase, Pin1, has been shown to play a role in the regulation of cell cycle progression, both in vitro and in vivo. However, the involvement of Pin1 during follicular development is not well understood. The aim of this study was first to investigate the expression of Pin1 mRNA in the granulosa and theca cells of the follicle at different developmental stages of follicles in the bovine ovary, and second, to examine the effects of follicle-stimulating hormone (FSH) and estradiol (E2) on the expression of Pin1 in the cultured bovine granulosa cells. Follicles were classified into four groups based on the diameter (dominant follicles >8.5mm in diameter, subordinate follicles <8.5mm in diameter) and the relative levels of E2 and progesterone (P4) (E2:P4>1, estrogen active; E2:P4<1, estrogen inactive): i.e. preovulatory dominant follicles (POFs); E2 active dominant follicles (EADs); E2 inactive dominant follicles (EIDs); small follicles (SFs). The expression of the Pin1 gene was significantly increased in the granulosa cells of EADs as compared with those of other follicles, whereas its expression in theca cells did not differ among follicles at different developmental stages. The concentration of 5ng/ml FSH alone and the combination of 1ng/ml E2 and 5ng/ml FSH stimulated the expression of the Pin1 gene in bovine granulosa cells. Our data provide the first evidence that Pin1 expression in the granulosa cells but not the theca cells changes during follicular development, and that FSH stimulate the expression of the Pin1 gene. These results suggest that Pin1 regulates the timing of cell proliferation and may act as an intracellular signal responder in the granulosa cells during bovine follicle development.
Ovarian localization
Oocyte
Comment
An Unusual Two Step Control of CPEB Destruction by Pin1. Nechama M et al. Cytoplasmic polyadenylation is a conserved mechanism that controls mRNA translation and stability. A key protein that promotes polyadenylation-induced translation of mRNAs in maturing Xenopus oocyte is the Cytoplasmic Polyadenylation Element Binding Protein (CPEB). During this meiotic transition, CPEB is subjected to phosphorylation-dependent ubiquitination and partial destruction, which is necessary for successive waves of polyadenylation of distinct mRNAs. Here we identify the peptidyl-prolyl cis-trans isomerase Pin1 as an important factor mediating CPEB destruction. Pin1 interacts with CPEB in an unusual manner in that it occurs prior to CPEB phosphorylation and prior to Pin1 activation by serine 71 dephosphorylation. Upon induction of maturation, CPEB becomes phosphorylated, which occurs simultaneously with Pin1 dephosphorylation. At this time, the CPEB-Pin1 interaction requires cdk1-catalyzed CPEB phosphorylation on S/TP motifs. Subsequent CPEB ubiquitination and destruction is mediated by a conformational change induced by Pin1 isomerization of CPEB. Similar to M-phase progression in maturing Xenopus oocytes, the destruction of CPEB during the mammalian cell cycle requires Pin1 as well. These data identify Pin1 as a new and essential factor regulating CPEB degradation.
Follicle stages
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Phenotypes
Mutations
1 mutations
Species: mouse
Mutation name: type: null mutation fertility: infertile - ovarian defect Comment: Pin1 regulates the timing of mammalian primordial germ cell proliferation. Atchison FW et al. (2003) Primordial germ cells (PGCs) give rise to male and female germ cells to transmit the genome from generation to generation. Defects in PGC development often result in infertility. In the mouse embryo, PGCs undergo proliferation and expansion during and after their migration to the gonads from 8.5 to 13.5 days post coitum (dpc). We show that a peptidyl-prolyl isomerase, Pin1, is involved in the regulation of mammalian PGC proliferation. We discovered that both the male and female Pin1(-/-) mice had profound fertility defects. Investigation of the reproductive organs revealed significantly fewer germ cells in the adult Pin1(-/-) testes and ovaries than in wild type or heterozygotes, which resulted from Pin1(-/-) males and females being born with severely reduced number of gonocytes and oocytes. Further studies in 8.5 to 13.5 dpc Pin1(-/-) embryos showed that PGCs were allocated properly at the base of the allantois, but their cell expansion was progressively impaired, resulting in a markedly reduced number of PGCs at 13.5 dpc. Analyses using markers of cell cycle parameters and apoptosis revealed that Pin1(-/-) PGCs did not undergo cell cycle arrest or apoptosis. Instead, Pin1(-/-) PGCs had a lower BrdU labeling index compared with wild-type PGCs. We conclude that PGCs have a prolonged cell cycle in the absence of Pin1, which translates into fewer cell divisions and strikingly fewer Pin1(-/-) PGCs by the end of the proliferative phase. These results indicate that Pin1 regulates the timing of PGC proliferation during mouse embryonic development.//////////////////