Interactions between the RNA Interference Effector Protein Ago1 and 14-3-3 Proteins

The Argonaute family member Ago1 is required for formation of pericentric heterochromatin and small interfering RNA (siRNA)-mediated post-transcriptional gene silencing in the fission yeast Schizosaccharomyces pombe. In addition, we have recently demonstrated that Ago1 function is required for enactment of cell cycle checkpoints (Carmichael, J. B., Provost, P., Ekwall, K., and Hobman, T. C. (2004) Mol. Biol. Cell 15, 1425-1435). Here, we provide evidence that the amino terminus of Ago1 binds to proteins that function in cell cycle regulation including 14-3-3 proteins. Interestingly, the amino terminus of human Ago2, the endonuclease that cleaves siRNA-targeted mRNAs, was also demonstrated to bind 14-3-3 proteins. Overexpression of the Ago1 amino terminus in yeast resulted in cell cycle delay at the G2/M boundary. Further investigation revealed that nuclear import of the mitosis-inducing phosphatase Cdc25 is inhibited by overexpression of the Ago1 amino terminus. Under these conditions, we found that the cyclin-dependent kinase Cdc2 is constitutively phosphorylated on tyrosine 15, thereby reducing the activity of this kinase, a situation that delays entry into mitosis. We hypothesize that 14-3-3 proteins are required for Argonaute protein functions in cell cycle and/or gene-silencing pathways. The Argonaute family member Ago1 is required for formation of pericentric heterochromatin and small interfering RNA (siRNA)-mediated post-transcriptional gene silencing in the fission yeast Schizosaccharomyces pombe. In addition, we have recently demonstrated that Ago1 function is required for enactment of cell cycle checkpoints (Carmichael, J. B., Provost, P., Ekwall, K., and Hobman, T. C. (2004) Mol. Biol. Cell 15, 1425-1435). Here, we provide evidence that the amino terminus of Ago1 binds to proteins that function in cell cycle regulation including 14-3-3 proteins. Interestingly, the amino terminus of human Ago2, the endonuclease that cleaves siRNA-targeted mRNAs, was also demonstrated to bind 14-3-3 proteins. Overexpression of the Ago1 amino terminus in yeast resulted in cell cycle delay at the G2/M boundary. Further investigation revealed that nuclear import of the mitosis-inducing phosphatase Cdc25 is inhibited by overexpression of the Ago1 amino terminus. Under these conditions, we found that the cyclin-dependent kinase Cdc2 is constitutively phosphorylated on tyrosine 15, thereby reducing the activity of this kinase, a situation that delays entry into mitosis. We hypothesize that 14-3-3 proteins are required for Argonaute protein functions in cell cycle and/or gene-silencing pathways. Argonaute proteins function in RNA interference (RNAi) 2The abbreviations used are: RNAi, RNA interference; HU, hydroxyurea; GST, glutathione S-transferase; CT, carboxyl terminal; NT, amino terminal; DAPI, 4,6-diamidino-2-phenylindole; RFP, red fluorescent protein; GFP, green fluorescent protein; EMM, essential minimal medium; PBS, phosphate-buffered saline; FACS, fluorescence-activated cell sorter; -F, forward; -R, reverse. 2The abbreviations used are: RNAi, RNA interference; HU, hydroxyurea; GST, glutathione S-transferase; CT, carboxyl terminal; NT, amino terminal; DAPI, 4,6-diamidino-2-phenylindole; RFP, red fluorescent protein; GFP, green fluorescent protein; EMM, essential minimal medium; PBS, phosphate-buffered saline; FACS, fluorescence-activated cell sorter; -F, forward; -R, reverse. (4Fire A. Xu S. Montgomery M.K. Kostas S.A. Driver S.E. Mello C.C. Nature. 1998; 391: 806-811Crossref PubMed a gene-silencing that in the of of the Argonaute family the of that gene silencing by in J. PubMed and Nature. PubMed that are to the Argonaute the to that the of that of in the human PubMed of the by the proteins including that and cell cycle of in the fission yeast Schizosaccharomyces to a of including the in to at the post-transcriptional A. PubMed this and gene silencing C. PubMed A. PubMed We are in the the yeast and cell cycle in the proteins in and to a in gene J. A. S. A. PubMed J. J. Mol. Cell Biol. PubMed revealed that the yeast the of the that are by RNAi, have in cell pathways. of these are and and that yeast Argonaute and proteins function in cell cycle in a that small interfering Mol. Biol. PubMed In addition, human Ago2, a of the silencing S. PubMed was to the in Mol. Biol. PubMed that have the to cell cycle in the of in cell cycle we a to cell cycle in In this we that Argonaute proteins 14-3-3 proteins. In these are for the of the cyclin-dependent kinase, of S. used in this and are in yeast at in yeast essential minimal C. J. The of yeast was the C. J. of the of the in The was used for of used in this of in a used in this of of in a in S. a Ago1 was by and and into the The was and in to the of the of PubMed to The and by the and of the and and by into the fluorescent protein was The and by the and The and and and and The a into the and of the T. Mol. Biol. PubMed we used Ago1 that a of The was the and and into a in the by in the was by the and and into the The was and and into for in of yeast in the of the at for was and at in to for in in and for The of in at and at to was to a of to of the and the for a at by at for at and in phosphate-buffered and by and the by at for at S. Cell in of to to of at by The by for in and by the protein for at in and the yeast at on a protein in and by and by to at the for of proteins in and proteins J. Biol. PubMed The of 14-3-3 proteins human proteins was by to 14-3-3 proteins was at in to the into was to of the to a of of the was for by in a to of on the of by on was to a of and the for by for at and by a Cdc2 and Cdc2 and to by for in a and on a was in for to to of and by in of in of in of and at for by of and at for to on a of the Ago1 Cell demonstrated that Ago1 function is required to the in fission yeast Mol. Biol. PubMed a are to in the of was to a of Ago1 that to HU, by enactment of the of the Ago1 that the the in the The into the S. in the of to overexpression of the proteins. and for Overexpression of the of Ago1 to to yeast the a on by of yeast the protein revealed that and The of the that to to these nuclear fission yeast have Cell Biol. PubMed and also to of the of in a a the of yeast a of In the of was that these and at the G2/M the of the we the cell cycle of this and to to yeast the to the cell cycle the is in yeast by for the of a that functions in cell S. PubMed the formation in fission the cell cycle to the of to a in the of in of yeast in cell cycle delay and yeast a in to of HU, cell cycle by in the of In yeast delay cell cycle to this the to the is that to HU, yeast are to the and PubMed a of these we that the a protein that for the cell cycle to the in to of yeast GST, HU, and the of at to 14-3-3 into on the cell cycle we used to proteins that bind to the amino terminus of The was in on and proteins the by and by of the proteins that the in by we to a of yeast proteins that to of these proteins was a member of the 14-3-3 The of protein was of 14-3-3 proteins have in cell cycle and enactment PubMed we to and Ago1 by and was used a for these is to a S. 14-3-3 that functions PubMed We also and Ago1 is Ago1 T. Mol. Cell Biol. PubMed 14-3-3 proteins and have we for 14-3-3 proteins and the human J. PubMed the of human Ago2, and 14-3-3 proteins was 14-3-3 proteins. was a protein in on and proteins and to and that to to by The the of the The of and are GST, proteins by and a the carboxyl terminus of to the of proteins used in the GST, in and proteins and by of Cdc25 and of functions to cell cycle and enactment of and a protein kinase required for the Mol. Biol. PubMed S. Nature. PubMed is by PubMed In to of the functions of is to the thereby 14-3-3 yeast and of of 14-3-3 proteins of this phosphatase the A. PubMed A. Nature. PubMed of Cdc25 to the phosphatase to the is in the A. Nature. PubMed of Cdc2 by Cdc25 is required for to in Nature. PubMed that Cdc25 activity in that are at G2/M Nature. PubMed we that Ago1 is required for of Cdc2 on tyrosine in to Mol. Biol. PubMed we that the of of Cdc25 to to and a that nuclear import of The yeast a at the of the C. C. PubMed was and the of was by of a of and is in that nuclear of and C. C. PubMed that a on nuclear import of in yeast this we a situation in nuclear is the that in nuclear import of Cdc25 these is that binds to and the function of the nuclear S. T. J. Biol. PubMed of fission yeast this to nuclear of Cdc25 Mol. Cell Biol. PubMed Under these conditions, in the nuclear was the of nuclear was in In addition, the of nuclear was to in that the that and C. was in these that was Cdc25 in these of in of tyrosine on in a yeast that a at the The of by the of are in yeast In the is in the of a yeast to and to Cdc2 and that of Cdc25 into the have on nuclear of the nuclear of Cdc25 is the Cdc2 in Cell Biol. PubMed of Cdc25 in the was to in of The of in yeast of Cdc2 was that at to yeast the of phosphorylated Cdc2 in yeast these that the delay overexpression of is in by a of Cdc25 to the we for the that the Argonaute proteins bind to 14-3-3 proteins in yeast and human Overexpression of the 14-3-3 of Ago1 in cell cycle delay at the G2/M We hypothesize that the of are to to bind 14-3-3 proteins. The of to of the Ago1 and human at the revealed 14-3-3 the at revealed the of 14-3-3 in the of human yeast is 14-3-3 bind to Argonaute proteins of a of 14-3-3 proteins to Cdc25 is required for enactment in to Mol. Cell Biol. PubMed and that this to the nuclear of Cdc25 A. Nature. PubMed of Cdc25 in the is to entry into mitosis. the is of the is required In this is that the protein the in the of the Cdc25 this is the protein of human is to delay cell cycle at the G2/M in by of 14-3-3 and in a that of Cdc25 T. A. A. J. PubMed that we and in the that functions in a to the that a by of Cdc25 14-3-3 proteins. In this is to that 14-3-3 proteins have also to function in nuclear import of Cdc25 Mol. Cell Biol. PubMed Under this overexpression of to the of 14-3-3 proteins for cell cycle Cdc25 by into situation also in of constitutively of in the in of by and revealed that the activity of Cdc2 in to Nature. PubMed is that the of is by the of these that is required for of Cdc2 Mol. Biol. PubMed The are a in Ago1 and the cell cycle and are required for this In nuclear import of the Cdc25 to of to and of Ago1 and In this is to that and human are and that is the of that binds to J. Biol. PubMed J. Biol. PubMed is also to the that 14-3-3 proteins are required for the function of Argonaute proteins in gene-silencing pathways. Argonaute proteins function in RNA interference (RNAi) 2The abbreviations used are: RNAi, RNA interference; HU, hydroxyurea; GST, glutathione S-transferase; CT, carboxyl terminal; NT, amino terminal; DAPI, 4,6-diamidino-2-phenylindole; RFP, red fluorescent protein; GFP, green fluorescent protein; EMM, essential minimal medium; PBS, phosphate-buffered saline; FACS, fluorescence-activated cell sorter; -F, forward; -R, reverse. 2The abbreviations used are: RNAi, RNA interference; HU, hydroxyurea; GST, glutathione S-transferase; CT, carboxyl terminal; NT, amino terminal; DAPI, 4,6-diamidino-2-phenylindole; RFP, red fluorescent protein; GFP, green fluorescent protein; EMM, essential minimal medium; PBS, phosphate-buffered saline; FACS, fluorescence-activated cell sorter; -F, forward; -R, reverse. (4Fire A. Xu S. Montgomery M.K. Kostas S.A. Driver S.E. Mello C.C. Nature. 1998; 391: 806-811Crossref PubMed a gene-silencing that in the of of the Argonaute family the of that gene silencing by in J. PubMed and Nature. PubMed that are to the Argonaute the to that the of that of in the human PubMed of the by the proteins including that and cell cycle The of in the fission yeast Schizosaccharomyces to a of including the in to at the post-transcriptional A. PubMed this and gene silencing C. PubMed A. PubMed We are in the the yeast and cell cycle in the proteins in and to a in gene J. A. S. A. PubMed J. J. Mol. Cell Biol. PubMed revealed that the yeast the of the that are by RNAi, have in cell pathways. of these are and and that yeast Argonaute and proteins function in cell cycle in a that small interfering Mol. Biol. PubMed In addition, human Ago2, a of the silencing S. PubMed was to the in Mol. Biol. PubMed that have the to cell cycle in the of in cell cycle we a to cell cycle in In this we that Argonaute proteins 14-3-3 proteins. In these are for the of the cyclin-dependent kinase, of S. used in this and are in yeast at in yeast essential minimal C. J. The of yeast was the C. J. of the of the in The was used for of used in this of in a used in this of of in a in S. a Ago1 was by and and into the The was and in to the of the of PubMed to The and by the and of the and and by into the fluorescent protein was The and by the and The and and and and The a into the and of the T. Mol. Biol. PubMed we used Ago1 that a of The was the and and into a in the by in the was by the and and into the The was and and into for in of yeast in the of the at for was and at in to for in in and for The of in at and at to was to a of to of the and the for a at by at for at and in phosphate-buffered and by and the by at for at S. Cell in of to to of at by The by for in and by the protein for at in and the yeast at on a protein in and by and by to at the for of proteins in and proteins J. Biol. PubMed The of 14-3-3 proteins human proteins was by to 14-3-3 proteins was at in to the into was to of the to a of of the was for by in a to of on the of by on was to a of and the for by for at and by a Cdc2 and Cdc2 and to by for in a and on a was in for to to of and by in of in of in of and at for by of and at for to on a of S. used in this and are in yeast at in yeast essential minimal C. J. The of yeast was the C. J. of the of the in The was used for of in S. a Ago1 was by and and into the The was and in to the of the of PubMed to The and by the and of the and and by into the fluorescent protein was The and by the and The and and and and The a into the and of the T. Mol. Biol. PubMed we used Ago1 that a of The was the and and into a in the by in the was by the and and into the The was and and into for in of yeast in the of the at for was and at in to for in in and for The of in at and at to was to a of to of the and the for a at by at for at and in phosphate-buffered and by and the by at for at S. Cell in of to to of at by The by for in and by the protein for at in and the yeast at on a protein in and by and by to at the for of proteins in and proteins J. Biol. PubMed The of 14-3-3 proteins human proteins was by to 14-3-3 proteins Cdc2 was at in to the into was to of the to a of of the was for by in a to of on the of by on was to a of and the for by for at and by a Cdc2 and Cdc2 and to by for in a and on a was in for to to of and by in of in of in of and at for by of and at for to on a of the Ago1 Cell demonstrated that Ago1 function is required to the in fission yeast Mol. Biol. PubMed a are to in the of was to a of Ago1 that to HU, by enactment of the of the Ago1 that the the in the The into the S. in the of to overexpression of the proteins. and for Overexpression of the of Ago1 to to yeast the a on by of yeast the protein revealed that and The of the that to to these nuclear fission yeast have Cell Biol. PubMed and also to of the of in a a the of yeast a of In the of was that these and at the G2/M the of the we the cell cycle of this and to to yeast the to the cell cycle the is in yeast by for the of a that functions in cell S. PubMed the formation in fission the cell cycle to the of to a in the of in of yeast in cell cycle delay and yeast a in to of HU, cell cycle by in the of In yeast delay cell cycle to this the to the is that to HU, yeast are to the and PubMed a of these we that the a protein that for the cell cycle to 14-3-3 into on the cell cycle we used to proteins that bind to the amino terminus of The was in on and proteins the by and by of the proteins that the in by we to a of yeast proteins that to of these proteins was a member of the 14-3-3 The of protein was of 14-3-3 proteins have in cell cycle and enactment PubMed we to and Ago1 by and was used a for these is to a S. 14-3-3 that functions PubMed We also and Ago1 is Ago1 T. Mol. Cell Biol. PubMed 14-3-3 proteins and have we for 14-3-3 proteins and the human J. PubMed the of human Ago2, and 14-3-3 proteins was 14-3-3 proteins. was a protein in on and proteins and to and that to to by The the of the The of and are GST, proteins by and a the carboxyl terminus of to the of proteins used in the GST, in and proteins and by of Cdc25 and of functions to cell cycle and enactment of and a protein kinase required for the Mol. Biol. PubMed S. Nature. PubMed is by PubMed In to of the functions of is to the thereby 14-3-3 yeast and of of 14-3-3 proteins of this phosphatase the A. PubMed A. Nature. PubMed of Cdc25 to the phosphatase to the is in the A. Nature. PubMed of Cdc2 by Cdc25 is required for to in Nature. PubMed that Cdc25 activity in that are at G2/M Nature. PubMed we that Ago1 is required for of Cdc2 on tyrosine in to Mol. Biol. PubMed we that the of of Cdc25 to to and a that nuclear import of The yeast a at the of the C. C. PubMed was and the of was by of a of and is in that nuclear of and C. C. PubMed that a on nuclear import of in yeast this we a situation in nuclear is the that in nuclear import of Cdc25 these is that binds to and the function of the nuclear S. T. J. Biol. PubMed of fission yeast this to nuclear of Cdc25 Mol. Cell Biol. PubMed Under these conditions, in the nuclear was the of nuclear was in In addition, the of nuclear was to in that the that and C. was in these that was Cdc25 in these of in of tyrosine on in a yeast that a at the The of by the of are in yeast In the is in the of a yeast to and to Cdc2 and that of Cdc25 into the have on nuclear of the nuclear of Cdc25 is the Cdc2 in Cell Biol. PubMed of Cdc25 in the was to in of The of in yeast of Cdc2 was that at to yeast the of phosphorylated Cdc2 in yeast these that the delay overexpression of is in by a of Cdc25 to Overexpression of the Ago1 Cell demonstrated that Ago1 function is required to the in fission yeast Mol. Biol. PubMed a are to in the of was to a of Ago1 that to HU, by enactment of the of the Ago1 that the the in the The into the S. in the of to overexpression of the proteins. and for Overexpression of the of Ago1 to to yeast the a on by of yeast the protein revealed that and The of the that to to these nuclear fission yeast have Cell Biol. PubMed and also to of the of in a a the of yeast a of In the of was that these and at the G2/M boundary. the of the we the cell cycle of this and to to yeast the to the cell cycle the is in yeast by for the of a that functions in cell S. PubMed the formation in fission the cell cycle to the of to a in the of in of yeast in cell cycle delay and yeast a in to of HU, cell cycle by in the of In yeast delay cell cycle to this the to the is that to HU, yeast are to the and PubMed a of these we that the a protein that for the cell cycle Argonaute to 14-3-3 into on the cell cycle we used to proteins that bind to the amino terminus of The was in on and proteins the by and by of the proteins that the in by we to a of yeast proteins that to of these proteins was a member of the 14-3-3 The of protein was of 14-3-3 proteins have in cell cycle and enactment PubMed we to and Ago1 by and was used a for these is to a S. 14-3-3 that functions PubMed We also and Ago1 is Ago1 T. Mol. Cell Biol. PubMed 14-3-3 proteins and have we for 14-3-3 proteins and the human J. PubMed the of human Ago2, and 14-3-3 proteins was Overexpression of Cdc25 and of functions to cell cycle and enactment of and a protein kinase required for the Mol. Biol. PubMed S. Nature. PubMed is by PubMed In to of the functions of is to the thereby 14-3-3 yeast and of of 14-3-3 proteins of this phosphatase the A. PubMed A. Nature. PubMed of Cdc25 to the phosphatase to the is in the A. Nature. PubMed of Cdc2 by Cdc25 is required for to in Nature. PubMed that Cdc25 activity in that are at G2/M Nature. PubMed we that Ago1 is required for of Cdc2 on tyrosine in to Mol. Biol. PubMed we that the of of Cdc25 to to and a that nuclear import of The yeast a at the of the C. C. PubMed was and the of was by of a of and is in that nuclear of and C. C. PubMed that a on nuclear import of in yeast this we a situation in nuclear is the that in nuclear import of Cdc25 these is that binds to and the function of the nuclear S. T. J. Biol. PubMed of fission yeast this to nuclear of Cdc25 Mol. Cell Biol. PubMed Under these conditions, in the nuclear was the of nuclear was in In addition, the of nuclear was to in that the that and C. was in these that was Cdc25 in these We that of Cdc25 into the have on nuclear of the nuclear of Cdc25 is the Cdc2 in Cell Biol. PubMed of Cdc25 in the was to in of The of in yeast of Cdc2 was that at to yeast the of phosphorylated Cdc2 in yeast these that the delay overexpression of is in by a of Cdc25 to the we for the that the Argonaute proteins bind to 14-3-3 proteins in yeast and human Overexpression of the 14-3-3 of Ago1 in cell cycle delay at the G2/M We hypothesize that the of are to to bind 14-3-3 proteins. The of to of the Ago1 and human at the revealed 14-3-3 the at revealed the of 14-3-3 in the of human yeast is 14-3-3 bind to Argonaute proteins of a of 14-3-3 proteins to Cdc25 is required for enactment in to Mol. Cell Biol. PubMed and that this to the nuclear of Cdc25 A. Nature. PubMed of Cdc25 in the is to entry into mitosis. the is of the is required In this is that the protein the in the of the Cdc25 this is the protein of human is to delay cell cycle at the G2/M in by of 14-3-3 and in a that of Cdc25 T. A. A. J. PubMed that we and in the that functions in a to the that a by of Cdc25 14-3-3 proteins. In this is to that 14-3-3 proteins have also to function in nuclear import of Cdc25 Mol. Cell Biol. PubMed Under this overexpression of to the of 14-3-3 proteins for cell cycle Cdc25 by into situation also in of constitutively of in the in of by and revealed that the activity of Cdc2 in to Nature. PubMed is that the of is by the of these that is required for of Cdc2 Mol. Biol. PubMed The are a in Ago1 and the cell cycle and are required for this In nuclear import of the Cdc25 to of to and of Ago1 and In this is to that and human are and that is the of that binds to J. Biol. PubMed J. Biol. PubMed is also to the that 14-3-3 proteins are required for the function of Argonaute proteins in gene-silencing pathways. In the we for the that the Argonaute proteins bind to 14-3-3 proteins in yeast and human Overexpression of the 14-3-3 of Ago1 in cell cycle delay at the G2/M We hypothesize that the of are to to bind 14-3-3 proteins. The of to of the Ago1 and human at the revealed 14-3-3 the at revealed the of 14-3-3 in the of human yeast is 14-3-3 bind to Argonaute proteins of a of 14-3-3 proteins to Cdc25 is required for enactment in to Mol. Cell Biol. PubMed and that this to the nuclear of Cdc25 A. Nature. PubMed of Cdc25 in the is to entry into mitosis. the is of the is required In this is that the protein the in the of the Cdc25 this is the protein of human is to delay cell cycle at the G2/M in by of 14-3-3 and in a that of Cdc25 T. A. A. J. PubMed that we and in the that functions in a to We the that a by of Cdc25 14-3-3 proteins. In this is to that 14-3-3 proteins have also to function in nuclear import of Cdc25 Mol. Cell Biol. PubMed Under this overexpression of to the of 14-3-3 proteins for cell cycle Cdc25 by into situation also in of constitutively of in the in of by and revealed that the activity of Cdc2 in to Nature. PubMed is that the of is by the of In these that is required for of Cdc2 Mol. Biol. PubMed The are a in Ago1 and the cell cycle and are required for this In nuclear import of the Cdc25 to of to and of Ago1 and In this is to that and human are and that is the of that binds to J. Biol. PubMed J. Biol. PubMed is also to the that 14-3-3 proteins are required for the function of Argonaute proteins in gene-silencing pathways. We and for of and

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.