TCTP is an Antiapoptotic Protein

8/10/2019 TCTP is an Antiapoptotic Protein

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TCTP is an antiapoptotic protein


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FIG. Sequence and structure of fortilin. A, sequence alignment of fortilin.The amino acid sequence of human fortilin was aligned to the

sequences of rabbit, mouse, chicken, Drosophila melanogaster,Caenorhabditis elegans, Saccharomyces cerevisiae, and rice, using asequence analysis program. Black and gray boxes represent amino acidsthat are identical and homologous, respectively, to those of human fortilin.The numbers in parentheses indicate GenBankTM accession numbers. Asshown here, fortilin is highly conserved among species. B, the domainstructure of fortilin. The amino acid sequence of fortilin was evaluated forits hydrophilicity using the GES ( black line) and von Heijne (gray line)methods. The middle one-third of fortilin (domain 2; amino acids 71 120;

isoelectroic point (pI) 9.01) is highly hydrophilic and sandwiched bydomain 1 (amino acids 1 70; pI 4.13) and domain 3 (amino acids 121 172; pI 4.75).


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FIG. The Northern blot analysis of fortilin. Northernblothybridization was carried out on multiple tissueblots of adult human mRNA using a radiolabeledfortilin cDNA probe. The -actin cDNA probe wasused to evaluate the amount of mRNA loaded ineach lane. The fortilin message was ubiquitous invarious human tissues and was especially abundantin the liver, kidney, small intestine, skeletalmuscle,and testis.

FIG. The characterization of anti-fortilin antibody and the evaluation of the expression patterns of fortilin. C, fortilinexpression in cell lines. Lysates from 2.5 104 cells of various lines were evaluated for fortilin expression with the anti-fortilinantibody characterized above. Fortilin expression was highly abundant in tumor cell lines of epithelial origin.


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FIG. tctp-wild-type and -mutant embryos at different stages of development. Hematoxylin eosin staining of sections ofparaffin-embedded E8.5 and E7.5 embryos are shown. Magnification: 4. Hematoxylin eosin (H&E) staining of sections ofparaffin-embedded E6.5 embryos is shown. Detection of apoptotic cells (red) was performed using TUNEL assay on sectionsof paraffin-embedded E6.5 embryos; the sections were counterstained using DAPI (blue). Magnification: 20.

Anchorage into the mitochondrialmembranes, antagonizing Bax


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TCTP interacts with Bcl-xL. ( a) Schematic representation of GST,GST-Bcl-xL, and GSTTCTP fusion proteins. ( b) Migration of purifiedGST, GST-Bcl-xL, and GST-TCTP on Coomassie blue-stained SDS PAGE (upper panel) and their specific reactivity on Western blot(lower panel) to GST-specific antibodies with bovine serumalbumin (BSA) as a negative control. ( c) GST pull-down assay. Onthe left panel, GST-Bcl-xL, but not GST, precipitated 35S-labelledTCTP (prepared by in vitro TNT). On the right panel, GST-TCTP, butnot GST, pulled down 35S-labelled Bcl-xL. ( d) Co-IP of endogenousTCTP with endogenous Bcl-xL. The co-IP was performed with anti-Bcl-xL antibodies, an Ig control, and an unrelated antibody control(anti-ASF/SF2), followed by Western blot with anti-TCTP antibodies.(e) Co-IP of endogenous Bcl-xL with endogenous TCTP. The co-IPwas performed with anti-TCTP antibodies, an Ig control, and anunrelated antibody control (antisplicing factor ASF/SF2), followedby Western blot with anti-Bcl-xL antibodies. ( f) Co- IP ofendogenous Mcl-1 with endogenous TCTP but not with Bcl-xL. As apositive control for TCTP interaction with a known partner, the co-IP was performed with anti-TCTP


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Fig (a) The different functions of TCTP and their potential mechanism of action. (b) Schematicrepresentation of the potential antiapoptotic mechanism of TCTP


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TCTP sebagai

anti apoptotic


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FIG. Overexpression of TCTP blocks Mcl-1 from undergoingubiquitination. (A) CHOP cells were transiently transfected withthe HA-mMcl-1 expression vector along with increasing amountsof the vector encoding FLAG-TCTP. At 16 h after transfection,cells were treated with MG-132 (2 M, lanes 1 to 4) or dimethylsulfoxide (vehicle control) (lanes 5 to 8) for 4 h before cell lysateswere prepared and immunoprecipitated with anti-mMcl-1antibody. The immune complex was then analyzed byimmunoblotting with anti-ubiquitin (UB) antibody (top panel).The ubiquitinated form of mMcl-1 is as indicated (UB-Mcl-1).Direct immunoblotting analysis of the corresponding cell lysates

(1/20 of those used in the top panel) with anti-HA and anti-FLAGantibodies are shown on the middle and the bottom panels,respectively. (B) The K257V mutant is more susceptible toundergoing ubiquitination. CHOP cells transiently overexpressingthe HA-tagged wild-type (lanes 1 and 3) or K257V mutant (lanes2 and 4) forms of mMcl-1 were treated and analyzed asdescribed in panel A. The ubiquitinated form of mMcl-1 (wild-type or mutant) is as indicated. The lower panel is a direct

immunoblotting analysis of cell lysates (1/20 of that used in theupper panel) with anti-HA antibody.


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TCTP is an antiapoptotic protein

TCTP plays a key role in the regulation of apoptosis.

Through its interaction with Mcl-1, TCTPregulates antiapoptotic activity by suppressingMcl-1 degradation by blocking its ubiquitination.

Fig. Regulation of TCTP protein stability: Hsp27 and Mcl-1protect TCTP to degradation and prevent apoptosis.


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Nevertheless, Graidist et al. reportedthat TCTP and Mcl-1 couldindependently protect cells fromapoptosis.

Fig. Schematic representation of the antiapoptotic functions of TCTP and interaction with protein involved incell death regulation.

TCTP is an Antiapoptotic Protein

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