Protein kinase and ATP-binding activity associated with the 72-kdalton single-stranded DNA-binding protein from early region 2A of human adenovirus type 5

1985 ◽  
Vol 63 (9) ◽  
pp. 941-952 ◽  
Author(s):  
Philip E. Branton ◽  
Mike Evelegh ◽  
David T. Rowe ◽  
Frank L. Graham ◽  
Silvia Bacchetti
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Human Adenovirus ◽  
Adenovirus Type ◽  
Atp Binding ◽  
Protein Kinase Activity ◽  
Wild Type ◽  
Amino Terminal ◽  
Early Region ◽  
Adenovirus Type 5

We have developed monoclonal antibodies which react specifically with the human adenovirus type 5 early region 2A 72-kdalton phosphoprotein (72 kDa) and its 48-kdalton proteolytic cleavage product (48 kDa) and have used these antibodies to study a number of properties of these viral polyeptides. Fluorescent antibody staining indicated that the 72 kDa was found almost entirely in the nucleus, generally in discreet patches. Preparations of the 72 kDa, purified by immunoprecipitation or by single-stranded DNA-cellulose column chromatography and incubated with [γ-32P]ATP, were found to contain protein kinase activity. Using photoaffinity labelling with 8-azido-[α-32P]ATP, the 72 kDa was shown to be an ATP-binding protein. The ATP-binding site was probably in the amino terminal region because the 48 kDa which lacks approximately 120 residues at the amino terminus failed to bind ATP. Experiments carried out with immunoprecipitates from wild-type and temperature-sensitive (ts125) infected cells suggested that the ts mutant-induced kinase activity was not more thermolabile than the wild-type protein. Thus although the present results indicated that protein kinase activity is associated with the 72 kDa, it is still unclear whether such activity is intrinsic to the 72 kDa or present in an enzyme associated with it. While it is probably not intrinsic to the carboxy terminal region affected by the ts125 mutation, it is still possible that it resides in an amino terminal domain.

Structural and functional modification of pp60c-src associated with polyoma middle tumor antigen from infected or transformed cells

1985 ◽  
Vol 5 (10) ◽  
pp. 2647-2652
Author(s):  
C A Cartwright ◽  
M A Hutchinson ◽  
W Eckhart
Keyword(s):  
Protein Kinase ◽  
Tyrosine Phosphorylation ◽  
Tumor Antigen ◽  
Kinase Activity ◽  
Protein Kinase Activity ◽  
Amino Terminal ◽  
Exogenous Substrate ◽  
And Function ◽  
Amino Terminal Domain

The polyoma middle tumor antigen (MTAg) associates with the src proto-oncogene product pp60c-src in infected or transformed rodent cells. The tyrosine protein kinase activity of pp60c-src, as measured by in vitro phosphorylation of pp60c-src itself or the exogenous substrate enolase, was increased 10- to 20-fold in cells transformed or infected with transformation-competent polyoma virus compared with controls. pp60c-src associated with MTAg and precipitated with polyoma antitumor serum had a novel site(s) of in vitro tyrosine phosphorylation within its amino-terminal domain. These observations suggest that association of MTAg with pp60c-src alters the accessibility of pp60c-src tyrosine residues for phosphorylation in vitro and increases pp60c-src protein kinase activity. Several transformation-defective mutants of MTAg did not cause amino-terminal tyrosine phosphorylation of pp60c-src in vitro or enhance its protein kinase activity, suggesting that these properties correlate with the transforming ability of MTAg. However, one transformation-defective MTAg mutant, dl1015, did cause amino-terminal tyrosine phosphorylation of pp60c-src in vitro and did enhance its protein kinase activity. This suggests that properties of MTAg, in addition to modifying the structure and function of pp60c-src, may be important for transformation.

Mapping of cellular protein-binding sites on the products of early-region 1A of human adenovirus type 5

1988 ◽  
Vol 8 (9) ◽  
pp. 3955-3959 ◽  
Author(s):  
C Egan ◽  
T N Jelsma ◽  
J A Howe ◽  
S T Bayley ◽  
B Ferguson ◽  
...  
Keyword(s):  
Biological Activity ◽  
Binding Sites ◽  
Human Adenovirus ◽  
Adenovirus Type ◽  
Cellular Protein ◽  
Cellular Proteins ◽  
Deletion Mutants ◽  
Protein Binding Sites ◽  
Amino Terminal ◽  
Adenovirus Type 5

The binding sites for the 300-, 107-, and 105-kilodalton cellular proteins which associate with human adenovirus type 5 E1A products were studied with E1A deletion mutants. All appeared to bind to the amino-terminal half of E1A products in regions necessary for oncogenic transformation. These results suggest that these cellular species may be important for the biological activity of E1A products.

A Wild-Type Nanopore Sensor for Protein Kinase Activity

2019 ◽  
Vol 91 (15) ◽  
pp. 9910-9915 ◽  
Author(s):  
Fu-Na Meng ◽  
Yi-Lun Ying ◽  
Jie Yang ◽  
Yi-Tao Long
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Protein Kinase Activity ◽  
Wild Type

scholarly journals Cell surface expression of v-fms-coded glycoproteins is required for transformation.

1984 ◽  
Vol 4 (10) ◽  
pp. 1999-2009 ◽  
Author(s):  
M F Roussel ◽  
C W Rettenmier ◽  
A T Look ◽  
C J Sherr
Keyword(s):  
Amino Acids ◽  
Protein Kinase ◽  
Cell Surface ◽  
Gene Product ◽  
Kinase Activity ◽  
Specific Protein ◽  
Protein Kinase Activity ◽  
Wild Type ◽  
Specific Protein Kinase

The viral oncogene v-fms encodes a transforming glycoprotein with in vitro tyrosine-specific protein kinase activity. Although most v-fms-coded molecules remain internally sequestered in transformed cells, a minor population of molecules is transported to the cell surface. An engineered deletion mutant lacking 348 base pairs of the 3.0-kilobase-pair v-fms gene encoded a polypeptide that was 15 kilodaltons smaller than the wild-type v-fms gene product. The in-frame deletion of 116 amino acids was adjacent to the transmembrane anchor peptide located near the middle of the predicted protein sequence and 432 amino acids from the carboxyl terminus. The mutant polypeptide acquired N-linked oligosaccharide chains, was proteolytically processed in a manner similar to the wild-type glycoprotein, and exhibited an associated tyrosine-specific protein kinase activity in vitro. However, the N-linked oligosaccharides of the mutant glycoprotein were not processed to complex carbohydrate chains, and the glycoprotein was not detected at the cell surface. Cells expressing high levels of the mutant glycoprotein did not undergo morphological transformation and did not form colonies in semisolid medium. The transforming activity of the v-fms gene product therefore appears to be mediated through target molecules on the plasma membrane.

scholarly journals Analysis of Synthesis, Stability, Phosphorylation, and Interacting Polypeptides of the 34-Kilodalton Product of Open Reading Frame 6 of the Early Region 4 Protein of Human Adenovirus Type 5

1999 ◽  
Vol 73 (2) ◽  
pp. 1245-1253 ◽  
Author(s):  
Dominique Boivin ◽  
Megan R. Morrison ◽  
Richard C. Marcellus ◽  
Emmanuelle Querido ◽  
Philip E. Branton
Keyword(s):  
Protein Synthesis ◽  
Human Adenovirus ◽  
Adenovirus Type ◽  
Open Reading Frame ◽  
Cellular Proteins ◽  
Cell Protein ◽  
Reading Frame ◽  
Early Region ◽  
Early Region 4 ◽  
Adenovirus Type 5

ABSTRACT The 34-kDa early-region 4 open reading frame 6 (E4orf6) product of human adenovirus type 5 forms complexes with both the cellular tumor suppressor p53 and the viral E1B 55-kDa protein (E1B-55kDa). E4orf6 can inhibit p53 transactivation activity, as can E1B-55kDa, and in combination these viral proteins cause the rapid turnover of p53. In addition, E4orf6-55kDa complexes play a critical role at later times in the regulation of viral mRNA transport and shutoff of host cell protein synthesis. In the present study, we have further characterized some of the biological properties of E4orf6. Analysis of extracts from infected cells by Western blotting indicated that E4orf6, like E1A and E1B products, is present at high levels until very late times, suggesting that it is available to act throughout the infectious cycle. This pattern is similar to that of E4orf4 but differs markedly from that of another E4 product, E4orf6/7, which is present only transiently. Synthesis of E4orf6 is maximal at early stages but ceases completely with the onset of shutoff of host protein synthesis; however, it was found that unlike E4orf6/7, E4orf6 is very stable, thus allowing high levels to be maintained even at late times. E4orf6 was shown to be phosphorylated at low levels. Coimmunoprecipitation studies in cells lacking p53 indicated that E4orf6 interacts with a number of other proteins. Five of these were shown to be viral or virally induced proteins ranging in size from 102 to 27 kDa, including E1B-55kDa. One such species, of 72 kDa, was shown not to represent the E2 DNA-binding protein and thus remains to be identified. Another appeared to be the L4 100-kDa nonstructural adenovirus late product, but it appeared to be present nonspecifically and not as part of an E4orf6 complex. Apart from p53, three additional cellular proteins, of 84, 19, and 14 kDa were detected by using an adenovirus vector that expresses only E4orf6. The 19-kDa species and a 16-kDa cellular protein were also shown to interact with E4orf6/7. It is possible that complex formation with these viral and cellular proteins plays a role in one or more of the biological activities associated with E4orf6 and E4orf6/7.

scholarly journals The Early Region 4 orf4 Protein of Human Adenovirus Type 5 Induces p53-Independent Cell Death by Apoptosis

1998 ◽  
Vol 72 (9) ◽  
pp. 7144-7153 ◽  
Author(s):  
Richard C. Marcellus ◽  
Josée N. Lavoie ◽  
Dominique Boivin ◽  
Gordon C. Shore ◽  
Gary Ketner ◽  
...  
Keyword(s):  
Cell Death ◽  
Human Adenovirus ◽  
Adenovirus Type ◽  
Cell Killing ◽  
Wild Type Virus ◽  
Dna Encoding ◽  
Early Region ◽  
Orf4 Protein ◽  
Early Region 4 ◽  
Adenovirus Type 5

ABSTRACT Previous studies by our group showed that infection of human and rodent cells by human adenovirus type 5 (Ad5) results in the induction of p53-independent apoptosis and cell death that are dependent upon transactivation of early region 4 (E4). To identify which E4 products are involved, studies were conducted with p53-deficient human SAOS-2 cells infected with various Ad5 E4 mutants. An E4orf6-deficient mutant was defective in cell killing, whereas another that expressed only E4orf6 and E4orf4 killed like wild-type virus, suggesting that E4orf6 may be responsible for cytotoxicity; however, a mutant expressing only E4orf4 induced high levels of cell death, indicating that this E4 product may also be able to induce cytotoxicity. To define the E4 cell death-inducing functions more precisely, cDNAs encoding individual E4 products were introduced into cells by DNA transfection in the absence of other Ad5 proteins. In cotransfections with a cDNA encoding firefly luciferase, enzymatic activity was high in all cases except with E4orf4, where luciferase levels were less than 20% of those in controls. In addition, drug selection of several cell types following transfection with retroviral vector DNA encoding individual E4 products as well as puromycin resistance yielded a large number of cell colonies except when E4orf4 was expressed. These data demonstrated that E4orf4 is the only E4 product capable of independent cell killing. Cell death induced by E4orf4 was due to apoptosis, as evidenced by 4′,6-diamidino-2-phenylindole (DAPI) staining of cell nuclei in E4orf4-expressing cells. Thus, although E4orf6 may play some role, these results suggested that E4orf4 may be the major E4 product responsible for induction of p53-independent apoptosis.

scholarly journals Activation of p56lck through mutation of a regulatory carboxy-terminal tyrosine residue requires intact sites of autophosphorylation and myristylation.

1990 ◽  
Vol 10 (10) ◽  
pp. 5197-5206 ◽  
Author(s):  
N Abraham ◽  
A Veillette
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Membrane Association ◽  
Protein Kinase Activity ◽  
Tyrosine Residue ◽  
Amino Terminal ◽  
Enzymatic Function ◽  
Tyrosine Protein Kinase ◽  
Carboxy Terminal

Mutation of the major site of in vivo tyrosine phosphorylation of p56lck (tyrosine 505) to a phenylalanine constitutively enhances the p56lck-associated tyrosine-specific protein kinase activity. The mutant polypeptide is extensively phosphorylated in vivo at the site of in vitro Lck autophosphorylation (tyrosine 394) and is capable of oncogenic transformation of rodent fibroblasts. These observations have suggested that phosphorylation at Tyr-505 down regulates the tyrosine protein kinase activity of p56lck. Herein we have attempted to examine whether other posttranslational modifications may be involved in regulation of the enzymatic function of p56lck. The results indicated that activation of p56lck by mutation of Tyr-505 was prevented by a tyrosine-to-phenylalanine substitution at position 394. Furthermore, activation of p56lck by mutation of the carboxy-terminal tyrosine residue was rendered less efficient by substituting an alanine residue for the amino-terminal glycine. This second mutation prevented p56lck myristylation and stable membrane association and was associated with decreased in vivo phosphorylation at Tyr-394. Taken together, these findings imply that lack of phosphorylation at Tyr-505 may be insufficient for enhancement of the p56lck-associated tyrosine protein kinase activity. Our data suggest that activation of p56lck may be dependent on phosphorylation at Tyr-394 and that this process may be facilitated by myristylation, membrane association, or both.

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