Biochemical and Biophysical Research Communications
Thymosin beta 4 expression and nuclear transport are regulated by hMLH1☆
Section snippets
Materials and methods
Bacterial Strains and cell lines. E. coli strains XL1-Blue MRF´ Kan, BacterioMatch Two-Hybrid reporter, and validation cells were purchased from Stratagene (La Jolla, CA). All media were prepared as described in the manufacturer’s protocol. HCT-116 cells deficient in hMLH1 (ATCC CCL247) as well as 293T cells, obtained from Dr. Kurt Ballmer (Paul Scherer Institute, Villingen, Switzerland), were grown in DMEM with 10% FCS. As previously published, MutLα is not expressed in 293T [20]. Stably
Results and discussion
During the last years several hMLH1-interacting partners have been identified by yeast two-hybrid. To circumvent the limitations inherent to the yeast system, like delicate identification of nuclear proteins, we applied a bacterial two-hybrid screening. We now report the identification of Tβ4, an actin-binding, and cell motility regulating protein [27], [28]. The physical interaction of hMLH1 with Tβ4 was verified by coimmunoprecipitation in a mammalian system (Fig. 1).
hMLH1 contains a
Acknowledgments
We thank Dr. Françoise Praz for donating the HCT-116 mlh 0–1 and HCT-116 mlh 1–2 cell line and Nicole Weber for performance of experiments.
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2020, Life SciencesCitation Excerpt :It has been reported that PTX3 was induced by oleic acid through AKT/NF-κB pathway and elevated the expression of MMP-3 and vimentin thus enhanced the interaction between tumor cells and endothelial cells, leading to tumor migration and invasion in HNSCC [37]. Tβ4, the most abundant member of the thymosin β family, is involved in neovascularization, anti-apoptosis and anti-inflammatory [38]. It has been found that Tβ4 is overexpressed in tumor tissues of human colon cancer, renal cell carcinoma, and rat osteosarcoma, and its expression level is related to tumor metastasis and stage [39].
DNA mismatch repair proteins MLH1 and PMS2 can be imported to the nucleus by a classical nuclear import pathway
2018, BiochimieCitation Excerpt :Considering the affinity results obtained here and also the more efficient transport of the full-length MLH1 compared to PMS2 [2], we suggest that MLH1 plays the major role in the nuclear transport of MutLα (MLH1/PMS2) complex. In addition, as MLH1 dimerizes with other partners (e.g. PMS1 and MLH3) to form other MutL complexes, its role in the import process of other complexes [2,53,54] is also probable. Possible explanations for the presence of NLS in PMS2 may include: (i) the observed basic sequences of residues for PMS2 is not functionally used for import processes; (ii) redundancy of the NLSs to guarantee the nuclear transport of the MutLα, as suggested by Leong and colleagues [24]; (iii) PMS2 may be involved in other important processes related to other complexes, although such processes have not been observed yet; and (iv) different affinities may be related to regulation of the import of DNA repair proteins.
Exome Sequencing Identifies Biallelic MSH3 Germline Mutations as a Recessive Subtype of Colorectal Adenomatous Polyposis
2016, American Journal of Human GeneticsThymosin Beta 4: A Potential Novel Therapy for Neurotrophic Keratopathy, Dry Eye, and Ocular Surface Diseases
2016, Vitamins and HormonesCitation Excerpt :Focal adhesion complex proteins contribute directly to TNF-α signaling transduction. Additional intracellular NF-kB activators or inhibitors anchored into both the nuclear matrix and cytoplasmic stress fibers have been shown to physically interact with NF-kB (Bednarek et al., 2008; Bock-Marquette et al., 2004; Brieger, Plotz, Zeuzem, & Trojan, 2007; Fazal, Minhajuddin, Bijli, McGrath, & Rahman, 2007; Lee, So, Park, & Kim, 2008; Zhang et al., 2006). Tβ4 is a major intracellular monomeric G-actin-sequestering molecule.
Intrinsic, Functional, and Structural Properties of β-Thymosins and β-Thymosin/WH2 Domains in the Regulation and Coordination of Actin Self-Assembly Dynamics and Cytoskeleton Remodeling
2016, Vitamins and HormonesCitation Excerpt :Tβ4 was first found to interact with a key enzyme of DNA mismatch repair, hMLH1 that is frequently mutated in human cancers. Since hMLH1 contains a canonical nuclear localization sequence (NLS), it was proposed to translocate Tβ4 into the nucleus where the latter may be involved in DNA mismatch repair and the regulation of cell mortality (Brieger, Plotz, Zeuzem, & Trojan, 2007). Tβ4 was also found to stimulate plasminogen activator inhibitor type 1 (PAI-1) gene expression in endothelial cells by interacting with the Ku80 subunit of ATP-dependent DNA helicase II (Bednarek et al., 2008).
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This study was supported by a grant from the Wilhelm Sander-Foundation (2005.085.1).