Identification of nuclear-import and cell-cycle regulatory proteins that bind to prothymosin α

Freire, Javier; Covelo, Guillermo; Sarandeses, Concepción S.; Díaz-Jullien, Cristina; Freire, Manuel

doi:10.1139/o00-098

Cited by 24 publications

(11 citation statements)

References 39 publications

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“…It is well accepted that prothymosin a concentrates mainly in the cell nucleus, while a small amount of the protein can be seen in the cytoplasm, and especially in perinuclear areas (Gomez-Marquez and Segade, 1998;Roson et al, 1990;Vareli et al, 1996;Rubtsov et al, 1997;Enkemann et al, 2000;Cotter and Robertson, 2000;Freire et al, 2001). The perinuclear concentrations of prothymosin a observed in this study (arrowead in Fig 3J) were found to be related to centrosomes/ microtubule organization centers (arrowead in Fig.…”

Section: Resultssupporting

confidence: 67%

Prothymosin α is localized in mitotic spindle during mitosis⋆

Vareli¹,

Frangou-Lazaridis²

2004

Biology of the Cell

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Prothymosin a is a small, acidic, ubiquitous protein, thought to play a role in cell proliferation, carcinogenesis and apoptosis. We have reported earlier that in the interphase nucleus prothymosin a exhibits a punctuated nuclear distribution associated with transcription sites. Moreover, the protein was found to localize in 1-6 subnuclear domains where PML and CstF64 proteins were also identified. In the present study we followed the subcellular distribution of prothymosin a during mitosis. Our data identify prothymosin a to colocalize with a-tubulin in the mitotic spindle throughout mitosis, and to decorate the midbody during cytokinesis. Moreover nocodazole treatment disrupted prothymosin a and a-tubulin colocalization at the centrosomes of the interphase cell. Prothymosin a was also found to decorate c-tubulin identified centrosomes, during mitosis. Taken together our colocalization study suggests involvement of prothymosin a, in the formation, maintenance, or functioning of the mitotic spindle.

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Section: Resultssupporting

confidence: 67%

Prothymosin α is localized in mitotic spindle during mitosis⋆

Vareli¹,

Frangou-Lazaridis²

2004

Biology of the Cell

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“…4). Because the thermally induced folding-unfolded profile of an oligomeric protein is dependent on the total protein concentration, the oligomerization state of a protein can be tested by carrying out DSC experiments at different protein concentrations (37). In the range of concentrations studied, the transition temperature of metal-free DtxR(C102D) is independent of the protein concentration, indicating that the protein behaves as a monomer.…”

Section: Resultsmentioning

confidence: 99%

Mechanism of metal ion activation of the diphtheria toxin repressor DtxR

Tetenbaum-Novatt

White

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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The diphtheria toxin repressor (DtxR) is a metal ion-activated transcriptional regulator that has been linked to the virulence of Corynebacterium diphtheriae. Structure determination has shown that there are two metal ion binding sites per repressor monomer, and site-directed mutagenesis has demonstrated that binding site 2 (primary) is essential for recognition of the target DNA repressor, leaving the role of binding site 1 (ancillary) unclear. Calorimetric techniques have demonstrated that although binding site 1 (ancillary) has high affinity for metal ion with a binding constant of 2 ؋ 10 ؊7 , binding site 2 (primary) is a low-affinity binding site with a binding constant of 6.3 ؋ 10 ؊4 . These two binding sites act in an independent fashion, and their contribution can be easily dissected by traditional mutational analysis. Our results clearly demonstrate that binding site 1 (ancillary) is the first one to be occupied during metal ion activation, playing a critical role in stabilization of the repressor. In addition, structural data obtained for the mutants Ni-DtxR(H79A,C102D), reported here, and the previously reported DtxR(H79A) have allowed us to propose a mechanism of metal activation for DtxR.iron ͉ homeostasis ͉ transcription regulation

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“…It is worth noting that PTMA interacts with basic proteins, including histones, thanks to the acidic residues clustered in the central region of the molecule (Diaz-Jullien et al, 1996). In addition to this, PTMA also shares some aspects with SubH2Bv: it has a bipartite nuclear localization signal (-KR-X 12 -KKQK-) at its carboxy terminal (Rubtsov et al, 1997) but has been described in the cytoplasm too (Piñeiro et al, 2000); it binds to nuclear transport proteins, like Ran, karyopherine B, transportin (Enkemann et al, 2000;Freire et al, 2001) and participates in nuclear import pathways ( Karapetian et al, 2005;Niture and Jaiswal, 2009). All of these features suggest that PTMA may interact with PT proteins and, as a consequence, be directly involved in the pathways of acrosome assembly and acrosome-nuclear docking.…”

Section: Discussionmentioning

confidence: 99%

Expression of prothymosin alpha in meiotic and post‐meiotic germ cells during the first wave of rat spermatogenesis

Ferrara¹,

Izzo²,

Pariante³

et al. 2010

Journal Cellular Physiology

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Prothymosin alpha (PTMA) is a highly acidic small polypeptide, that is, widely distributed and conserved among mammals. Its possible involvement in male gametogenesis has been mentioned but not clarified yet; in particular, it has been suggested that, in non-mammalian vertebrates, it could play a role during GC meiosis and differentiation. In the present work we investigated the possible association between PTMA and meiotic and post-meiotic phases of mammalian spermatogenesis. Three different time points during postnatal development of rat testis were analyzed, that is, 27 dpp (completed meiosis), 35 dpp (occurring spermiogenesis), and 60 dpp (first wave of spermatogenesis definitely ended). RT-PCR and Western blot analyses showed that the expression levels of both Ptma mRNA and corresponding protein decrease in total extracts from 27 to 60 dpp. The in situ hybridization localized the transcript in interstitial Leydig cells, peritubular myoid cells and, inside the tubules, in germ cells from pachytene spermatocytes to newly formed haploid spermatids. The immunohistochemistry analysis localized the protein in the same cell types at 27 dpp, while at 35 and 60 dpp the haploid cells remain the only germ cells that still express it. In particular, PTMA specific localization in the heads of spermatids and epididymal spermatozoa, associated with the acrosome system, supports for the first time the hypothesis of a direct function in male germ cells.

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Identification of nuclear-import and cell-cycle regulatory proteins that bind to prothymosin α

Cited by 24 publications

References 39 publications

Prothymosin α is localized in mitotic spindle during mitosis⋆

Prothymosin α is localized in mitotic spindle during mitosis⋆

Mechanism of metal ion activation of the diphtheria toxin repressor DtxR

Expression of prothymosin alpha in meiotic and post‐meiotic germ cells during the first wave of rat spermatogenesis

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