| 36 matches found in 11 documents. Search time: 0.058 seconds. |
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Score: 10.00 |
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| Title: Diversity of Arabidopsis genes encoding precursors for phytosulfokine , a peptide growth factor .
| | Author: Yang H Matsubayashi Y Nakamura K Sakagami Y | | Journal: Plant Physiol .
Citation: V : 127 ( 3 ) P : 842-51 Year: 2001 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub11706167 Accession (PMID): 11706167 | | Abstract: Phytosulfokine-alpha ( PSK-alpha ) , a unique plant peptide growth factor , was originally isolated from conditioned medium of asparagus ( Asparagus officinalis ) mesophyll cell cultures .
PSK-alpha has several biological activities including promoting plant cell proliferation .
Four genes that encode precursors of PSK-alpha have been identified from Arabidopsis .
Analysis of cDNAs for two of these , AtPSK2 and AtPSK3 , shows that both of these genes consist of two exons and one intron .
The predicted precursors have N-terminal signal peptides and only a single PSK-alpha sequence located close to their carboxyl termini .
Both precursors contain dibasic processing sites flanking PSK , analogous to animal and yeast prohormones .
Although the PSK domain including the sequence of PSK-alpha and three amino acids preceding it are perfectly conserved , the precursors bear very limited similarity among Arabidopsis and rice ( Oryza sativa ) , suggesting a new level of diversity among polypeptides that are processed into the same signaling molecule in plants , a scenario not found in animals and yeast Unnatural [ serine-4 ] PSK-beta was found to be secreted by transgenic Arabidopsis cells expressing a mutant of either AtPSK2 or AtPSK3 cDNAs , suggesting that both AtPSK2 and AtPSK3 encode PSK-alpha precursors .
AtPSK2 and AtPSK3 were expressed demonstrably not only in cultured cells but also in intact plants , suggesting that PSK-alpha may be essential for plant cell proliferation in vivo as well as in vitro .
Overexpression of either precursor gene allowed the transgenic calli to grow twice as large as the controls .
However , the transgenic cells expressing either antisense cDNA did not dramatically decrease mitogenic activity , suggesting that these two genes may act redundantly . | Matching Sentences:
[ Sen. 7, subscore: 4.00 ]: Although the PSK domain including the sequence of PSK-alpha and three amino acids preceding it are perfectly conserved , the precursors bear very limited similarity among Arabidopsis and rice ( Oryza sativa ) , suggesting a new level of diversity among polypeptides that are processed into the same signaling molecule in plants , a scenario not found in animals and yeast Unnatural [ serine-4 ] PSK-beta was found to be secreted by transgenic Arabidopsis cells expressing a mutant of either AtPSK2 or AtPSK3 cDNAs , suggesting that both AtPSK2 and AtPSK3 encode PSK-alpha precursors .
[ Sen. 1, subscore: 1.00 ]: Phytosulfokine-alpha ( PSK-alpha ) , a unique plant peptide growth factor , was originally isolated from conditioned medium of asparagus ( Asparagus officinalis ) mesophyll cell cultures .
[ Sen. 2, subscore: 1.00 ]: PSK-alpha has several biological activities including promoting plant cell proliferation .
[ Sen. 3, subscore: 1.00 ]: Four genes that encode precursors of PSK-alpha have been identified from Arabidopsis .
[ Sen. 5, subscore: 1.00 ]: The predicted precursors have N-terminal signal peptides and only a single PSK-alpha sequence located close to their carboxyl termini .
[ Sen. 6, subscore: 1.00 ]: Both precursors contain dibasic processing sites flanking PSK , analogous to animal and yeast prohormones .
[ Sen. 8, subscore: 1.00 ]: AtPSK2 and AtPSK3 were expressed demonstrably not only in cultured cells but also in intact plants , suggesting that PSK-alpha may be essential for plant cell proliferation in vivo as well as in vitro .
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Score: 8.00 |
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| Title: Oryza sativa PSK gene encodes a precursor of phytosulfokine-alpha , a sulfated peptide growth factor found in plants .
| | Author: Yang H Matsubayashi Y Nakamura K Sakagami Y | | Journal: Proc . Natl . Acad . Sci . USA Citation: V : 96 ( 23 ) P : 13560-5 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10557360 Accession (PMID): 10557360 | | Abstract: Phytosulfokine-alpha [ PSK-alpha , Tyr ( SO ( 3 ) H ) -Ile-Tyr ( SO ( 3 ) H ) -Thr-Gln ] , a sulfated mitogenic peptide found in plants , strongly promotes proliferation of plant cells in culture at very low concentrations .
Oryza sativa PSK ( OsPSK ) cDNA encoding a PSK-alpha precursor has been isolated .
The cDNA is 725 base pairs long , and the 89-aa product , preprophytosulfokine , has a 22-aa hydrophobic region that resembles a cleavable leader peptide at its NH ( 2 ) terminus .
The PSK-alpha sequence occurs only once within the precursor , close to the COOH terminus .
[ Ser ( 4 ) ] PSK-alpha was secreted by transgenic rice Oc cells harboring a mutated OsPSK cDNA , suggesting proteolytic processing from the larger precursor , a feature commonly found in animal systems .
Whereas PSK-alpha in conditioned medium with sense transgenic Oc cells was 1 . 6 times as concentrated as in the control case , antisense transgenic Oc cells produced less than 60% of the control level .
Preprophytosulfokine mRNA was detected at an elevated constitutive level in rice Oc culture cells on RNA blot analysis .
Although PSK-alpha molecules have never been identified in any intact plant , reverse transcription-PCR analysis demonstrated that OsPSK is expressed in rice seedlings , indicating that PSK-alpha may be important for plant cell proliferation both in vitro and in vivo .
DNA blot analysis demonstrated that OsPSK homologs may occur in dicot as well as monocot plants . | Matching Sentences:
[ Sen. 2, subscore: 2.00 ]: Oryza sativa PSK ( OsPSK ) cDNA encoding a PSK-alpha precursor has been isolated .
[ Sen. 8, subscore: 2.00 ]: Although PSK-alpha molecules have never been identified in any intact plant , reverse transcription-PCR analysis demonstrated that OsPSK is expressed in rice seedlings , indicating that PSK-alpha may be important for plant cell proliferation both in vitro and in vivo .
[ Sen. 1, subscore: 1.00 ]: Phytosulfokine-alpha [ PSK-alpha , Tyr ( SO ( 3 ) H ) -Ile-Tyr ( SO ( 3 ) H ) -Thr-Gln ] , a sulfated mitogenic peptide found in plants , strongly promotes proliferation of plant cells in culture at very low concentrations .
[ Sen. 4, subscore: 1.00 ]: The PSK-alpha sequence occurs only once within the precursor , close to the COOH terminus .
[ Sen. 5, subscore: 1.00 ]: [ Ser ( 4 ) ] PSK-alpha was secreted by transgenic rice Oc cells harboring a mutated OsPSK cDNA , suggesting proteolytic processing from the larger precursor , a feature commonly found in animal systems .
[ Sen. 6, subscore: 1.00 ]: Whereas PSK-alpha in conditioned medium with sense transgenic Oc cells was 1 . 6 times as concentrated as in the control case , antisense transgenic Oc cells produced less than 60% of the control level .
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Score: 8.00 |
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| Title: 120 and 160-kDa receptors for endogenous mitogenic peptide , phytosulfokine-alpha , in rice plasma membranes .
| | Author: Matsubayashi Y Sakagami Y | | Journal: J Biol . Chem . Citation: V : 275 ( 20 ) P : 15520-5 Year: 2000 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10809784 Accession (PMID): 10809784 | | Abstract: Plant cells in culture secrete a sulfated peptide named phytosulfokine-alpha ( PSK-alpha ) , and this peptide induces the cell division and/or cell differentiation by means of specific high and low affinity receptors .
Putative receptor proteins for this autocrine type growth factor were identified by photoaffinity labeling of plasma membrane fractions derived from rice suspension cells .
Incubation of membranes with a photoactivable ( 125 ) I-labeled PSK-alpha analog , [ N ( epsilon ) - ( 4-azidosalicyl ) Lys ( 5 ) ] PSK-alpha ( AS-PSK-alpha ) , followed by UV irradiation resulted in specific labeling of 120 and 160-kDa bands in SDS-polyacrylamide gel electrophoresis .
The labeling of both bands was completely inhibited by unlabeled PSK-alpha and partially decreased by PSK-alpha analogs possessing moderate binding activities .
In contrast , PSK-alpha analogs that have no biological activity showed no competition for ( 125 ) I-AS-PSK-alpha binding , confirming the specificity of binding proteins .
Analysis of the affinity of ( 125 ) I incorporation into the protein by ligand saturation experiments gave apparent K ( d ) values of 5 . 0 nm for the 120-kDa band and 5 . 4 nm for the 160-kDa band , suggesting that both proteins correspond to the high affinity binding site .
Treatment of ( 125 ) I-AS-PSK-alpha cross-linked proteins with peptide N-glycosidase F demonstrated that both proteins contained approximately 10 kDa of N-linked oligosaccharides .
Specific cross-linking of ( 125 ) I-AS-PSK-alpha was also observed by using plasma membranes derived from carrot and tobacco cells , indicating the widespread occurrence of the binding proteins .
Together , these data suggest that the 120 and 160-kDa proteins are PSK-alpha receptors that mediate the biological activities of PSK-alpha . | Matching Sentences:
[ Sen. 3, subscore: 2.00 ]: Incubation of membranes with a photoactivable ( 125 ) I-labeled PSK-alpha analog , [ N ( epsilon ) - ( 4-azidosalicyl ) Lys ( 5 ) ] PSK-alpha ( AS-PSK-alpha ) , followed by UV irradiation resulted in specific labeling of 120 and 160-kDa bands in SDS-polyacrylamide gel electrophoresis .
[ Sen. 4, subscore: 2.00 ]: The labeling of both bands was completely inhibited by unlabeled PSK-alpha and partially decreased by PSK-alpha analogs possessing moderate binding activities .
[ Sen. 9, subscore: 2.00 ]: Together , these data suggest that the 120 and 160-kDa proteins are PSK-alpha receptors that mediate the biological activities of PSK-alpha .
[ Sen. 1, subscore: 1.00 ]: Plant cells in culture secrete a sulfated peptide named phytosulfokine-alpha ( PSK-alpha ) , and this peptide induces the cell division and/or cell differentiation by means of specific high and low affinity receptors .
[ Sen. 5, subscore: 1.00 ]: In contrast , PSK-alpha analogs that have no biological activity showed no competition for ( 125 ) I-AS-PSK-alpha binding , confirming the specificity of binding proteins .
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Score: 7.00 |
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| Title: Characterization of specific binding sites for a mitogenic sulfated peptide , phytosulfokine-alpha , in the plasma-membrane fraction derived from Oryza sativa L | | Author: Matsubayashi Y Sakagami Y | | Journal: Eur .
J Biochem .
Citation: V : 262 ( 3 ) P : 666-71 Year: 1999 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub10411626 Accession (PMID): 10411626 | | Abstract: Treatment of rice cells with an endogenous mitogenic peptide , phytosulfokine-alpha ( PSK-alpha ) , results in cell proliferation .
In the present study , [ 3H ] PSK-alpha prepared by catalytic reduction of a PSK-alpha analog containing tetradehydroisoleucine was employed to identify putative PSK-alpha target molecules on rice plasma membranes .
Membrane binding of the ligand was found to be saturable , reversible and pH dependent .
Scatchard analysis demonstrated the existence of both high and low-affinity binding sites with Kd values of 1 . 4 nM and 27 nM , respectively .
Competition studies with [ 3H ] PSK-alpha and several PSK-alpha analogs showed that displacing activity closely corresponds to the ability to induce cell proliferation .
The properties of the binding sites distributed on plasma membranes are consistent with the function of PSK-alpha receptors in activating a cascade of molecular events involved in plant cell proliferation . | Matching Sentences:
[ Sen. 2, subscore: 3.00 ]: In the present study , [ 3H ] PSK-alpha prepared by catalytic reduction of a PSK-alpha analog containing tetradehydroisoleucine was employed to identify putative PSK-alpha target molecules on rice plasma membranes .
[ Sen. 5, subscore: 2.00 ]: Competition studies with [ 3H ] PSK-alpha and several PSK-alpha analogs showed that displacing activity closely corresponds to the ability to induce cell proliferation .
[ Sen. 1, subscore: 1.00 ]: Treatment of rice cells with an endogenous mitogenic peptide , phytosulfokine-alpha ( PSK-alpha ) , results in cell proliferation .
[ Sen. 6, subscore: 1.00 ]: The properties of the binding sites distributed on plasma membranes are consistent with the function of PSK-alpha receptors in activating a cascade of molecular events involved in plant cell proliferation .
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Score: 6.00 |
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| Title: Phytosulfokine-alpha , a sulfated pentapeptide , stimulates the proliferation of rice cells by means of specific high and low-affinity binding sites .
| | Author: Matsubayashi Y Takagi L Sakagami Y | | Journal: Proc . Natl . Acad . Sci . USA Citation: V : 94 ( 24 ) P : 13357-62 Year: 1997 Type: ARTICLE | | Literature: oryza Field: abstract Doc ID: pub9371850 Accession (PMID): 9371850 | | Abstract: Peptide growth factors were isolated from conditioned medium derived from rice ( Oryza sativa L ) suspension cultures and identified to be a sulfated pentapeptide [ H-Tyr ( SO3H ) -Ile-Tyr ( SO3H ) -Thr-Gln-OH ] and its C-terminal-truncated tetrapeptide [ H-Tyr ( SO3H ) -Ile-Tyr ( SO3H ) -Thr-OH ] .
These structures were identical to the phytosulfokines originally found in asparagus ( Asparagus officinalis L ) mesophyll cultures .
The pentapeptide [ phytosulfokine-alpha ( PSK-alpha ) ] very strongly stimulated colony formation of rice protoplasts at concentrations above 10 ( -8 ) M , indicating a similar mode of action in rice of phytosulfokines .
Binding assays using 35S-labeled PSK-alpha demonstrated the existence of both high and low-affinity specific saturable binding sites on the surface of rice cells in suspension .
Analysis of [ 35S ] PSK-alpha binding in differential centrifugation fractions suggested association of the binding with a plasma membrane-enriched fraction .
The apparent Kd values for [ 35S ] PSK-alpha binding were found to be 1 x 10 ( -9 ) M for the high-affinity type and 1 x 10 ( -7 ) M for the low-affinity type , with maximal numbers of binding sites of 1 x 10 ( 4 ) sites per cell and 1 x 10 ( 5 ) sites per cell , respectively .
Competition studies with [ 35S ] PSK-alpha and several synthetic PSK-alpha analogs demonstrated that only peptides that possesses mitogenic activity can effectively displace the radioligand .
These results suggest that a signal transduction pathway mediated by peptide factors is involved in plant cell proliferation . | Matching Sentences:
[ Sen. 7, subscore: 2.00 ]: Competition studies with [ 35S ] PSK-alpha and several synthetic PSK-alpha analogs demonstrated that only peptides that possesses mitogenic activity can effectively displace the radioligand .
[ Sen. 3, subscore: 1.00 ]: The pentapeptide [ phytosulfokine-alpha ( PSK-alpha ) ] very strongly stimulated colony formation of rice protoplasts at concentrations above 10 ( -8 ) M , indicating a similar mode of action in rice of phytosulfokines .
[ Sen. 4, subscore: 1.00 ]: Binding assays using 35S-labeled PSK-alpha demonstrated the existence of both high and low-affinity specific saturable binding sites on the surface of rice cells in suspension .
[ Sen. 5, subscore: 1.00 ]: Analysis of [ 35S ] PSK-alpha binding in differential centrifugation fractions suggested association of the binding with a plasma membrane-enriched fraction .
[ Sen. 6, subscore: 1.00 ]: The apparent Kd values for [ 35S ] PSK-alpha binding were found to be 1 x 10 ( -9 ) M for the high-affinity type and 1 x 10 ( -7 ) M for the low-affinity type , with maximal numbers of binding sites of 1 x 10 ( 4 ) sites per cell and 1 x 10 ( 5 ) sites per cell , respectively .
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