Identification and Characterization of Novel Isoforms of Human DP-1

Ishida, Hironori; Masuhiro, Yoshikazu; Fukushima, Akie; Argueta, Jose Guillermo Martinez; Yamaguchi, Noboru; Shiota, Susumu; Hanazawa, Shigemasa

doi:10.1074/jbc.m500189200

Cited by 21 publications

(12 citation statements)

References 28 publications

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“…Moreover, co-transfection of TFDP1 was able to partially overcome the inhibitory effect of TFDP3 on colony formation. In this context, it is worth mentioning a recent report on the identification of a novel and inhibitory isoform of TFDP1, DP1␣ (41). Inhibition by DP1␣ is obviously via a different mechanism, since it fails to bind to E2F due to the FIGURE 6.…”

Section: Discussionmentioning

confidence: 99%

Human TFDP3, a Novel DP Protein, Inhibits DNA Binding and Transactivation by E2F

Qiao

Stefano

Tian

et al. 2007

Journal of Biological Chemistry

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The two known DP proteins, TFDP1 and -2, bind E2Fs to form heterodimers essential for high affinity DNA binding and efficient transcriptional activation/repression. Here we report the identification of a new member of the DP family, human TFDP3. Despite the high degree of sequence similarity, TFDP3 is apparently distinct from TFDP1 in function. Although TFDP3 retained the capacity to bind to E2F proteins, the resulting heterodimers failed to interact with the E2F consensus sequence. In contrast to the stimulatory effect of TFDP1, TFDP3 inhibited E2F-mediated transcriptional activation. Consistent with this observation, we found that ectopic expression of TFDP3 impaired cell cycle progression from G 1 to S phase instead of facilitating such a transition as TFDP1 does. Sequence substitution analysis indicated that the DNA binding domain of TFDP3 was primarily responsible for the lack of DNA binding ability of E2F-TFDP3 heterodimers and the inhibition of E2F-mediated transcriptional activation. Fine mapping further revealed four amino acids in this region, which were critical for the functional conversion from activation by TFDP1 to suppression by TFDP3. In conclusion, these studies identify a new DP protein and a novel mechanism whereby E2F function is regulated.

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Section: Discussionmentioning

confidence: 99%

Human TFDP3, a Novel DP Protein, Inhibits DNA Binding and Transactivation by E2F

Qiao

Stefano

Tian

et al. 2007

Journal of Biological Chemistry

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“…For example, recently, a new member of the DP family, DP-3, was reported (25,26). As for DP-1 isoforms, we also previously identified 2 new isoforms (DP-1␣ and -␤) of DP-1 (27). DP-3 and DP-1␣ exhibited an inhibitory effect on E2F/DP-1 transcriptional activity (25)(26)(27).…”

mentioning

confidence: 77%

“…cDNA fragments of SOCS-3 deletions were amplified from full-length SOCS-3 cDNA by PCR using specific primers and Pyrobest DNA polymerase (Takara). GFP-DP-1 and 6xMyc-DP-1 expression plasmids were previously described (27). hDP-2 cDNA also was amplified from a human testis cDNA library (BD Biosciences) by PCR using specific primers (forward, 5Ј-ATGATTATAAGCACACCACAGAGACTAACCAGTTC-AGG-3Ј; reverse, 5Ј-GAAACGTAGGCTTTCTCTTGTCTT-TATTCTGGGGAG-3Ј).…”

Section: Methodsmentioning

confidence: 99%

“…Cell Culture and Transfection of HEK 293 Cells-Human embryonic kidney (HEK) 293 cells were cultured at 37°C with 5% CO 2 in Dulbecco's modified Eagle's medium (DMEM; Sigma) containing 100 units/ml penicillin, 100 g/ml streptomycin, and 10% fetal calf serum (Thermo Trace) as previously described (27). For the luciferase and cell growth assays, plasmids and siRNAs were introduced into HEK 293 cells using Lipofectamine 2000 (Invitrogen).…”

Section: Methodsmentioning

confidence: 99%

“…As for DP-1 isoforms, we also previously identified 2 new isoforms (DP-1␣ and -␤) of DP-1 (27). DP-3 and DP-1␣ exhibited an inhibitory effect on E2F/DP-1 transcriptional activity (25)(26)(27). Although DP-2 has a clear nuclear localization signal (NLS) and is localized in nuclei (28), DP-1 and -3 have no clear NLS; and some of these proteins reside in the cytoplasm.…”

mentioning

confidence: 94%

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SOCS-3 Inhibits E2F/DP-1 Transcriptional Activity and Cell Cycle Progression via Interaction with DP-1

Masuhiro

Kayama

Fukushima

et al. 2008

Journal of Biological Chemistry

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Recent studies using SOCS family knock-out mice have suggested that SOCS proteins have multiple biological functions in addition to their role as negative regulators of JAK-STAT signaling. To explore these other functions of this family of proteins, we used yeast two-hybrid screening to find proteins interacting with human SOCS-3. We identified the transcriptional factor DP-1 as a SOCS-3-interacting protein involved in regulation of the cell cycle. Immunoprecipitation-Western blot assay showed that this interaction between these endogenous proteins occurred in cells both in vitro and in vivo. SOCS-3 interacted with the C-terminal region of DP-1, and amino acids 156 -172 of SOCS-3 were required for this interaction. Confocal microscopy revealed that SOCS-3 and DP-1 were primarily colocalized in the cytoplasm. SOCS-3 inhibited E2F/DP-1 transcriptional activity under the cyclin-E promoter and actually inhibited cell cycle progression and cell growth under E2F/DP-1 control. In contrast, DP-1 almost completely eliminated the inhibitory action of SOCS-3 on LIF-stimulated STAT-3 transcriptional activity in JAK-STAT signaling. Interestingly, the alternative regulatory action of SOCS-3 and DP-1 was dramatically eliminated by each siRNA. Taken together, these findings demonstrate that SOCS-3 acts as a negative regulator of the cell cycle progression under E2F/DP-1 control by interfering with heterodimer formation between DP-1 and E2F and also that DP-1 plays an important role in controlling JAK-STAT signaling.Members of the family of suppressor of cytokine signaling (SOCS), 2 designated SOCS-1 to SOCS-7 and CIS, are induced by stimulation via several kinds of cytokines and growth factors (1-3). These proteins regulate JAK-STAT signaling in a classical negative feedback loop of the signaling cascade (4, 5). SOCS family proteins also act as an important regulator of cell differentiation, as evidenced by the following findings: SOCS-1 suppresses muscle differentiation (6); SOCS-2 regulates neuronal differentiation (7); SOCS-3 induces myoblast differentiation (8); and SOCS-3 and SOCS-5 are involved in T helper cell differentiation (9, 10). In addition, these proteins are thought to strongly contribute to the development and progression of several kinds of tumors such as hepatocellular carcinoma (11-13), chronic myeloid leukemia (14), ovarian and breast carcinoma (15), and so on (16 -21). These observations suggested to us that SOCS family proteins might exhibit multipotential functions as regulators of cell differentiation and tumor cell growth besides being a negative regulator of JAK-STAT signaling. To explore this possibility, we considered that identification of SOCS-interacting proteins would be an extraordinarily good strategy. Thus, using the yeast two-hybrid screening system, we sought to identify presently proteins interacting with human SOCS-3. As a result, we found DP-1, a transcriptional factor for cell cycle regulation, to be such a SOCS-3-interacting protein.DP-1 was first identified as a partner protein of E2F-...

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Plantamajoside inhibits the proliferation and epithelial‐to‐mesenchymal transition in hepatocellular carcinoma cells via modulating hypoxia‐inducible factor‐1α‐dependent gene expression

Yin

et al. 2020

Cell Biology International

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As a potential antitumor herbal medicine, plantamajoside (PMS) benefits the treatment of many human malignances. However, the role of PMS in the progression of hepatocellular carcinoma (HCC) and the related molecular mechanisms is still unknown. Here, we proved that the cell viabilities of HepG2 cells were gradually decreased with the increasing concentrations of CoCl2 and/or PMS via cell counting kit‐8 assay. Meanwhile, 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) and western blot assays were used to further confirm that PMS inhibited the CoCl2‐induced cell proliferation in HepG2 cells via suppressing the Ki67 and proliferating cell nuclear antigen expressions. We also performed wound‐healing and transwell assays and demonstrated that PMS inhibited CoCl2‐induced migration and invasion in HepG2 cells via suppressing the epithelial–mesenchymal transition (EMT) process. In addition, the use of 3‐(5′‐hydroxymethyl‐2′‐furyl)‐1‐benzylindazole further proved that PMS inhibited the malignant biological behaviors of HepG2 cells under hypoxic condition by suppressing the hypoxia‐inducible factor‐1α (HIF‐1α) expression. Besides, we further confirmed that PMS suppressed the growth and metastasis of implanted tumors in vivo. Given that PMS suppressed the proliferation and EMT induced by CoCl2 in HCC cells via downregulating HIF‐1α signaling pathway, we provided evidence that PMS might be a novel anti‐cancer drug for HCC treatment.

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Identification and Characterization of Novel Isoforms of Human DP-1

Cited by 21 publications

References 28 publications

Human TFDP3, a Novel DP Protein, Inhibits DNA Binding and Transactivation by E2F

Human TFDP3, a Novel DP Protein, Inhibits DNA Binding and Transactivation by E2F

SOCS-3 Inhibits E2F/DP-1 Transcriptional Activity and Cell Cycle Progression via Interaction with DP-1

Plantamajoside inhibits the proliferation and epithelial‐to‐mesenchymal transition in hepatocellular carcinoma cells via modulating hypoxia‐inducible factor‐1α‐dependent gene expression

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