Isolation and partial characterization of prothymosin α from porcine tissues

Economou, Michael; Seferiadis, K.; Frangou-Lazaridis, Maria; Horecker, B.L.; Tsolas, Orestes

doi:10.1016/0014-5793(88)80456-3

Cited by 33 publications

(28 citation statements)

References 16 publications

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“…Like huntingtin, the protein has multiple clustered caspase recognition sites, suggesting mandated cleavage. The three sites are found in prothymosin ␣ from all species (Eschenfeldt and Berger, 1986;Goodall et al, 1986;Economou et al, 1988;Panneerselvam et al, 1988;Frillingos et al, 1991;Schmidt and Werner, 1991) with the single exception of the rat (Haritos et al, 1985), which retains two of them. (2) Cleaved prothymosin ␣ appears to surrender its nuclear location, whereas the intact protein remains predominantly, if not exclusively, nuclear.…”

Section: Discussionmentioning

confidence: 98%

Functional discontinuities in prothymosin ? caused by caspase cleavage in apoptotic cells

Enkemann¹,

Wang²,

Trumbore³

et al. 2000

J. Cell. Physiol.

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Our study examines the effect of apoptosis on prothymosin alpha, an abundant, nuclear protein intimately involved with proliferation of all mammalian cells. When HeLa cells were treated with actinomycin D, with etoposide, or with staurosporine following synchronization with hydroxyurea, they underwent apoptosis based on several specific criteria, including fragmentation of DNA and activation of specific caspases. Similarly treated NIH3T3 cells arrested and displayed no indicators of apoptosis. In HeLa, but not in NIH3T3 cells, prothymosin alpha levels declined precipitously and a truncated version of the protein was formed. The following observations implicate caspase activity: (1) The truncated polypeptide arose only in the treated HeLa cell cultures. (2) The appearance of the truncated polypeptide coincided with the activation of caspase 3 and the cleavage of poly(ADP-ribose) polymerase, a known caspase substrate. (3) Carbobenzoxy-DEVD-fluoromethylketone, a cell-permeable caspase 3 inhibitor, blocked cleavage and degradation of prothymosin alpha. (4) The same inhibitor, when added to mixed extracts of apoptotic and normal cells, prevented cleavage of intact prothymosin alpha. (5) Recombinant caspase 3 and, to a much lesser extent, caspase 7 truncated purified prothymosin alpha. (6) In HeLa cells, cleavage occurred at three overlapping caspase 3-like sites with the consensus sequence D-X-X-D and released 10 to 14 residues from the carboxyl terminus, including the core nuclear localization signal. Two immediate consequences of the cleavage were observed: truncated prothymosin alpha was no longer confined to the nucleus and it was deficient in phosphate. These data suggest that the disabling of prothymosin alpha is a significant event in apoptosis. J. Cell. Physiol. 182:256-268, 2000. Published 2000 Wiley-Liss, Inc.

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Section: Discussionmentioning

confidence: 98%

Functional discontinuities in prothymosin ? caused by caspase cleavage in apoptotic cells

Enkemann¹,

Wang²,

Trumbore³

et al. 2000

J. Cell. Physiol.

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“…Prothymosin ␣ is a small, highly acidic (1, 2), nuclear (3)(4)(5)(6) protein found in virtually all mammalian tissues (7)(8)(9)(10)(11). Under conditions of rapid growth, a cultured cell accumulates upwards of 17 million molecules, a number roughly equivalent to that of histone cores (12).…”

mentioning

confidence: 99%

Turnover of the Acyl Phosphates of Human and Murine Prothymosin α in Vivo

Wang

Tao

Trumbore

et al. 1997

Journal of Biological Chemistry

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Prothymosin ␣ is a small, highly acidic, abundant, nuclear, mammalian protein which is essential for cell growth. Our laboratory has recently shown that primate prothymosin ␣ contains stoichiometric amounts of phosphate on the glutamyl groups of the protein and that in vitro the phosphate undergoes rapid hydrolysis or transfer to a nearby serine residue. Here an assay for the presence of acyl phosphates in vivo has been developed by measuring stable phosphoserine and phosphothreonine in vitro. The assay was used to determine the half-life of the acyl phosphates on prothymosin ␣ in vivo by pulse-labeling HeLa cells with [ 32 P]orthophosphate and chasing using three different techniques: permeabilization with digitonin to allow extracellular ATP to equilibrate with the intracellular pool; electroporation in the presence of ATP to reduce the specific activity of Prothymosin ␣ is a small, highly acidic (1, 2), nuclear (3-6) protein found in virtually all mammalian tissues (7-11). Under conditions of rapid growth, a cultured cell accumulates upwards of 17 million molecules, a number roughly equivalent to that of histone cores (12). When cells are disrupted with detergents, the protein readily leaks out of the nucleus, suggesting that stable interactions with nucleosomes or with the nuclear matrix are not an inherent part of its activity (2, 3). Its precise function is unknown. Nevertheless, a role in cell proliferation has been proposed based on the following observations: prothymosin ␣ mRNA is plentiful only in rapidly dividing cells (13)(14)(15); the level of the protein declines 10-fold in cells forced to subsist in stationary phase (12); the amount of prothymosin ␣ is directly proportional to the proliferative activity of the tissue from which it is isolated (13); and the uptake of antisense oligodeoxyribonucleotides directed toward various locations in prothymosin ␣ mRNA prevents synchronized human myeloma cells from entering mitosis (16). Hence, a deficiency in prothymosin ␣ is associated with failure to complete the cell cycle.Prothymosin ␣ has several unusual features. The human protein, which is almost identical to that of all other mammals (17), has 109 amino acids, nearly 50% of which are acidic (1, 2). A potent nuclear localization signal consisting of five basic amino acids has been identified near the carboxyl terminus (3, 6), while a second cluster of five basic residues near the amino terminus has no unambiguous role (3,18). The absence of all aromatic residues renders the protein transparent at 280 nm; it also lacks methionine, cysteine, and histidine. Based on biophysical data, it is believed to have an unfolded structure (19), a conclusion consistent with the presence of only seven widely dispersed hydrophobic residues in the human protein. Prothymosin ␣ does not bind SDS and stains anomalously with silver stain (2). The protein and the peptides derived from it exhibit poor immunogenicity. However, due to yet another aberrant property, the ability to partition quantitatively into the aqueous phase ...

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“…ProT~ is a highly acidic 12.5 kDa polypeptide originally isolated from rat thymus [1,2] and subsequently detected in a wide range of organisms and tissues [3][4][5]. There is a high degree of homology among the ProT~ and ProTa cDNAs of different species [6 11].…”

Section: Introductionmentioning

confidence: 99%

The prothymosin α gene is specifically expressed in ectodermal and mesodermal regions during early postimplantation mouse embryogenesis

Amo¹,

Freire²

1995

FEBS Letters

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Prothymosin a (ProTa) is a highly acidic nuclear protein, once believed to have an extracellular immunoregulatory role but more recently implicated in cell proliferation and/or differentiation. Several recent studies have revealed that ProTa mRNA is present during embryogenesis. However, these studies did not investigate the spatial distribution of ProTa mRNA in the embryo. Here we present a detailed study of the spatial distribution of ProTa mRNA during the early stages of postimplantation development (6.5--12.5 dpc) of the mouse. Three findings are of particular interest. First, ProTa mRNA levels increase during the early postimplantation stages (6.5-8.5 dpc) of mouse embryogenesis. Second, ProTcx mRNA is not uniformly distributed in the mouse embryo, but is present in a spatially specific manner. Third, we have observed that the mouse ProTa gene is expressed almost exclusively in ectodermal and mesoderm-derived structures, and not in cells which give rise to the definitive endoderm.

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Isolation and partial characterization of prothymosin α from porcine tissues

Cited by 33 publications

References 16 publications

Functional discontinuities in prothymosin ? caused by caspase cleavage in apoptotic cells

Functional discontinuities in prothymosin ? caused by caspase cleavage in apoptotic cells

Turnover of the Acyl Phosphates of Human and Murine Prothymosin α in Vivo

The prothymosin α gene is specifically expressed in ectodermal and mesodermal regions during early postimplantation mouse embryogenesis

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