On the molecular size of thymosins

Haritos, A.A.; Yialouris, P.P.; Heimer, Edgar P.; Félix, Arthur; Rosemeyer, Michael A.

doi:10.1016/0014-5793(87)81028-1

Cited by 18 publications

(7 citation statements)

References 31 publications

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“…Actually thymosin ␤ 4 is retarded by 10 kDa cutoff membranes (data not shown) and shows in gel filtration an apparent molecular mass of 17-21 kDa. 16,17 Its polarity, structure, and the resulting apparent size could be the reason that thymosin ␤ 4 is not able to diffuse through the nuclear pore of cytoplasm-depleted cells.…”

Section: Resultsmentioning

confidence: 99%

Subcellular Distribution of Thymosin β₄

Zoubek

Hannappel

2007

Annals of the New York Academy of Sciences

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The localization of Oregon Green cadaverine-labeled thymosin beta(4), its fragments, and variants was investigated in cytoplasm-depleted A431 cells and in microinjected cells without and with fixation. The studied thymosin beta(4) variants included substitutions of the lysine residues within the basic cluster (14-KSKLKK-19) and the actin-binding motif (17-LKKTETQ-23). In contrast to Oregon Green cadaverine, none of the variants or fragments of thymosin beta(4) could pass the intact nuclear pore of cytoplasm-depleted cells and were hence excluded from the nucleus. However, an equal distribution of all thymosin beta(4) variants was observed in living cells. The nuclear localization is neither dependent on the actin-binding ability of thymosin beta(4) nor on its basic lysine cluster. The equal distribution of the beta-thymosins, the ability of the fragments thymosin beta(4)(1-26) and beta(4)(27-43) to enter the nucleus in intact cells immediately after injection, and their exclusion from cytoplasm-depleted nuclei make it unlikely that they are transported by a single transport protein. A passive but regulated diffusion could explain the described ability of thymosin beta(4) to shuttle into the nucleus.

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Section: Resultsmentioning

confidence: 99%

Subcellular Distribution of Thymosin β₄

Zoubek

Hannappel

2007

Annals of the New York Academy of Sciences

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“…Similarly, prothymosin a is rich in negative charge, plentiful, probably unfolded (Watts et al, 1989(Watts et al, , 1990, and stable. It has been reported to undergo oligomerization (Haritos et al, 1984a(Haritos et al, , 1987Palvimo & Linnala-Kankkunen, 1990), becomes phosphorylated, does not associate stably with nuclear components (Sburlati et al, 1990), and promptly diffuses out of the nucleus during preparative procedures (Manrow et al, 1991). More importantly, it possesses an acidic motif virtually identical to the presumed histone binding region of nucleoplasmin (Burgh et al, 1987;Dingwall et al, 1987;R.…”

Section: Structurementioning

confidence: 92%

Phosphorylation of human and bovine prothymosin .alpha. in vivo

Sburlati

Rosa²,

Batey³

et al. 1993

Biochemistry

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Prothymosin alpha is post-translationally modified. When human myeloma cells were metabolically labeled with [32P]orthophosphoric acid, they synthesized [32P]prothymosin alpha. The incorporated radioactivity was resistant to DNase and RNases A, T1, and T2, but could be completely removed by alkaline phosphatase. No evidence was found for an RNA adduct as postulated by Vartapetian et al. [Vartapetian, A., Makarova, T., Koonin, E. V., Agol, V. I., & Bogdanov, A. (1988) FEBS Lett. 232, 35-38]. Thin-layer electrophoresis of partially hydrolyzed [32P]prothymosin alpha indicated that serine residues were phosphorylated. Analysis of peptides derived from bovine prothymosin alpha and human [32P]prothymosin alpha by treatment with endoproteinase Lys-C revealed that the amino-terminal 14-mer, with serine residues at positions 1, 8, and 9, was phosphorylated at a single position. Approximately 2% of the peptide in each case contained phosphate. Further digestion of the phosphopeptide with Asp-N followed by C18 reversed-phase column chromatography produced two peptides: a phosphate-free 9-mer containing amino acids 6-14 and a labeled peptide migrating slightly faster than the N-terminal 5-mer derived from the unmodified 14-mer. Positive identification of the phosphorylated amino acid was obtained by colliding the 14-residue phosphopeptide with helium in the mass spectrometer and finding phosphate only in a nested set of phosphorylated fragments composed of the first three, four, and five amino acids. The results prove that prothymosin alpha contains N-terminal acetylserine phosphate. In a synchronized population of human myeloma cells, phosphorylation occurred throughout the cell cycle. Furthermore, prothymosin alpha appeared to be stable, with a half-life slightly shorter than the generation time. Although prothymosin alpha is known to be essential for cell division, the constancy of both the amount of the protein and the degree of its phosphorylation suggests that prothymosin alpha does not directly govern mitosis.

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“…They are divided into three main groups according to their isoelectric points (IP): α-thymosins (IP < pH 5.0), β-thymosins (IP ranging from pH 5.0 to 7.0), and γ -thymosins (IP > pH 7.0) (3,4). β-Thymosins contain highly conserved acidic 5 kDa peptides consisting of 40-44 amino acid residues, of which 50% are charged (4,5). To date, there are at least 15 β-thymosins identified in species ranging from various invertebrates to vertebrates (2,6), and they are thought to be localized in either the nucleus or cytoplasm (7,8) and can interact with monomeric G-actins (9)(10)(11).…”

Section: Introductionmentioning

confidence: 99%

Advances in Thymosin β10 Research: Differential Expression, Molecular Mechanisms, and Clinical Implications in Cancer and Other Conditions

Sribenja¹,

Li²,

Wongkham³

et al. 2009

Cancer Investigation

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Thymosin beta 10 (Tbeta10) is a member of the beta-thymosin family, which has biological activities as an actin-sequestering protein involved in cell motility. Tbeta10 may be correlated with tumor biology such as cell proliferation, apoptosis, angiogenesis, and metastasis behavior. However, the molecular mechanisms of action of Tbeta10 in cancer are largely unknown. Tbeta10 is differentially expressed in embryogenesis and neuronal development. Its expression is also increased in many inflammatory conditions and tumorigenesis. This review briefly summarizes recent advances in Tbeta10 research including differential expression, functions, mechanisms, gene regulation, and therapeutic applications in cancer, wound healing, and other diseases.

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On the molecular size of thymosins

Cited by 18 publications

References 31 publications

Subcellular Distribution of Thymosin β₄

Subcellular Distribution of Thymosin β₄

Phosphorylation of human and bovine prothymosin .alpha. in vivo

Advances in Thymosin β10 Research: Differential Expression, Molecular Mechanisms, and Clinical Implications in Cancer and Other Conditions

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On the molecular size of thymosins

Cited by 18 publications

References 31 publications

Subcellular Distribution of Thymosin β4

Subcellular Distribution of Thymosin β4

Phosphorylation of human and bovine prothymosin .alpha. in vivo

Advances in Thymosin β10 Research: Differential Expression, Molecular Mechanisms, and Clinical Implications in Cancer and Other Conditions

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Product

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Subcellular Distribution of Thymosin β₄

Subcellular Distribution of Thymosin β₄