| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| The properties and developmental regulation of vertebrate polysialyltransferase ( PST ) , an enzyme activity responsible for extension of alpha 2 , 8 linked sialic acid homopolymers ( PSA ) associated with the fifth Ig domain of the neural cell adhesion molecule ( NCAM ) . have been studied . ^^^ The assay for PST used exogenous NCAM as a substrate , with a PSA specific endoneuraminidase as a control for specificity . ^^^ The developmental regulation both of PST activity and of the addition of PSA to NCAM were studied in chick whole brain , tectum , and cerebellum and found to be precisely coordinated . ^^^ However in direct tests of this hypothesis in transfected cells the presence of VASE did not markedly alter the level of NCAM polysialylation or alter the affinity of PST for the NCAM substrate . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Recently , hamster and human cDNAs encoding polysialyltransferase ( PST 1 for the hamster enzyme and PST for the human enzyme ) were cloned , and by using the human cDNA it was demonstrated that the expression of PSA in N CAM facilitates neurite outgrowth ( Nakayama , J . , Fukuda , M . ^^^ Here we demonstrate that PSA formation by PST is independent from the presence of N CAM in vivo . ^^^ We then develop an in vitro assay of PSA synthesis using glycoproteins other than N CAM as acceptors and a soluble PST as an enzyme source . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Using incompletely glycosylated NCAM variants and soluble recombinant glycosyltransferases , we reconstituted the site at which PST 1 acts to polysialylate NCAM in vitro . ^^^ The data presented here clearly demonstrate that polysialylation of NCAM is catalyzed by a single enzyme , PST 1 , and that terminal sialylation of the N glycan core is sufficient to generate the PSA acceptor site . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| In contrast to the polysialylation of NCAM , where terminal sialylation in either the alpha 2 , 3 or alpha 2 , 6 position is required , the autopolysialylation could be started in the asialo PST 1 isolated from CHO cells of the Lec 2 complementation group . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| PST and STX are polysialyltransferases that form polysialic acid in the neural cell adhesion molecule ( N CAM ) , although it is not known why these two polysialyltransferases exist . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Hamster PST 1 ( PST ) and rat STX are two related sialytransferases that catalyze the polysialylation of N CAM . ^^^ The distribution of PST and STX mRNAs , polysialic acid , and N CAM were analyzed at three developmental stages . ^^^ The results suggest that both PST and STX participate in the polysialylation of N CAM in vivo and that their expression levels are dynamically controlled during development and regeneration . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Polysialyltransferase ( PST ) is an enzyme that catalyzes the addition of polysialic acid ( PSA ) , a homopolymer of alpha 2 , 8 linked sialic acid residues , onto neural cell adhesion molecule ( NCAM ) . ^^^ The expression of PSA NCAM in the brain is developmentally regulated and is of critical importance ; however , the temporal and spatial developmental expression of brain PST , a potential key player in the control of PSA NCAM levels , remains unclear . ^^^ The developmental profile of PST mRNA is paralleled in some structures by that of the PSA NCAM , there are , however , notable exceptions . ^^^ Therefore , our results demonstrate that expression of rat PST mRNA is developmentally regulated , is present in the adult rat brain in restricted areas and may be involved in regulating temporal and spatial expression of PSA NCAM . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Western blotting with an anti NCAM polyclonal antibody showed that NCAM was expressed as the polysialylated form in both ST8Sia 2 cDNA transfected and ST8Sia 4 cDNA transfected Neuro2a cells , but that the polysialylated NCAMs expressed in ST8Sia 4 cDNA transfected clones migrated much slower on SDS PAGE than those expressed in ST8Sia 2 cDNA transfected clones . ^^^ The slower migration of polysialylated NCAM of the ST8Sia 4 cDNA transfected clone ( N2a 4 ) than that of the ST8Sia 2 cDNA transfected clone ( N2a 2 ) was also observed when cells were metabolically labeled with [ 3H ] glucosamine or pulse chase labeled with [ 35S ] methionine followed by immunoprecipitation with anti PSA antibody or anti NCAM monoclonal antibody . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| It has been shown that two enzymes , polysialyltransferase , PST , and sialyltransferase 10 , STX , form polysialic acid on N CAM . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| PST and STX are polysialyltransferases that form polysialic acid in the neural cell adhesion molecule ( NCAM ) , and these two polysialyltransferases often exist together in the same tissues . ^^^ To determine the individual and combined roles of PST and STX in polysialic acid synthesis , in the present study we asked if PST and STX differ in the acceptor requirement and if PST and STX act together in polysialylation of NCAM . ^^^ We first examined whether PST and STX differ in the requirement of sialic acid and core structures of N glycans attached to NCAM . ^^^ PST and STX were found to add polysialic acid on NCAM . ^^^ These results indicate that both PST and STX have relatively broad specificity on N glycan core structures in NCAM and no remarkable difference exists between PST and STX for the requirement of core structures and sialic acid attached to the N glycans of NCAM . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Comparisons between PST and another polysialyltransferase , sialyltransferase 10 ( STX ) , are made and it is demonstrated that both enzymes can independently form polysialic acid in vitro , but that during neural development they coordinately but distinctly synthesize polysialic acid on N CAM . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| PST ( ST8Sia 4 ) and STX ( ST8Sia 2 ) are the two polysialyltransferases responsible for NCAM polysialylation . ^^^ PST ( ST8Sia 4 ) and STX ( ST8Sia 2 ) are the two polysialyltransferases responsible for NCAM polysialylation . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Two enzymes , the polysialyltransferases ST8SiaII and ST8SiaIV , are known to be involved in the polysialylation of NCAM . ^^^ For this purpose , PC 12 cells , which endogenously express NCAM , were transfected with ST8SiaIV to produce , for the first time , a stable polysialylated PC 12 cell . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Polysialyltransferase 1 ( PST ; ST8Sia 4 ) is one of the alpha 2 , 8 polysialyltransferases responsible for the polysialylation of the neural cell adhesion molecule ( NCAM ) . ^^^ Co expression of the PST Asn mutants with NCAM demonstrated that autopolysialylation is not required for PST polysialyltransferase activity . ^^^ Immunoblot analyses of NCAM polysialylation by polysialylated and non autopolysialylated PST suggests that the NCAM is polysialylated to a higher degree by autopolysialylated PST . ^^^ We conclude that autopolysialylation of PST is not required for , but does enhance , NCAM polysialylation . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| So far , two polysialyltransferase enzymes , STX and PST , have been characterized for their capacity to transfer PSA onto NCAM in vitro . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Differential biosynthesis of polysialic acid on neural cell adhesion molecule ( NCAM ) and oligosaccharide acceptors by three distinct alpha 2 , 8 sialyltransferases , ST8Sia 4 ( PST ) , ST8Sia 2 ( STX ) , and ST8Sia 3 . ^^^ Polysialylation of NCAM was shown to be achieved by two alpha 2 , 8 polysialyltransferases , ST8Sia 4 ( PST ) and ST8Sia 2 ( STX ) , which are moderately related to another alpha 2 , 8 sialyltransferase , ST8Sia 3 . ^^^ By using a newly established method , we found that ST8Sia 4 , ST8Sia 2 , and ST8Sia 3 all add oligosialic and polysialic acid on various sialylated N acetyllactosaminyl oligosaccharides , including NCAM N glycans , fetuin N glycans , synthetic sialylated N acetyllactosamines , and on alpha ( 2 ) HS glycoprotein . ^^^ Polysialylation of NCAM by ST8Sia 4 and ST8Sia 2 is much more efficient than polysialylation of N glycans isolated from NCAM . ^^^ Moreover , ST8Sia 4 and ST8Sia 2 catalyze polysialylation of NCAM much more efficiently than ST8Sia 3 . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Second , it suggests that synthesis of di and / or oligo Sia units may be catalyzed by alpha 2 > 8 sialyltransferase ( s ) that are distinct from the known polysialyltransferases , STX and PST , which are partially responsible for polysialylation of N CAM . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| We used gene targeting to generate mice lacking ST8SiaIV / PST 1 , one of the polysialyltransferases responsible for addition of polysialic acid ( PSA ) to NCAM . ^^^ Furthermore , delamination of mossy fibers in the hippocampal CA 3 region , as found in NCAM deficient mice , does not occur in ST8SiaIV mutants . ^^^ Contrary to NCAM mutant mice , LTP in ST8SiaIV mutants was undisturbed at mossy fiber CA 3 synapses , which do not express PSA in wild type mice . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Control of NCAM polysialylation by the differential expression of polysialyltransferases ST8SiaII and ST8SiaIV . ^^^ Our data indicate that ST8SiaIV is the major regulator of NCAM polysialylation in vivo . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| In vitro and transfection approaches revealed that ST8SiaII and ST8SiaIV are independently capable of synthesizing PSA on NCAM with slightly different specificities towards the major NCAM isoforms and glycosylation sites . ^^^ Our data indicate that the increased expression of ST8SiaIV enables an accelerated polysialylation of NCAM , which , however , is not converted into higher amounts of PSA . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| ST8Sia 2 ( STX ) and ST8Sia 4 ( PST ) are polysialic acid ( polySia ) synthases that catalyze polySia formation of neural cell adhesion molecule ( NCAM ) in vivo and in vitro . ^^^ ST8Sia 4 catalyzed larger polySia formation of NCAM than ST8Sia 2 . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Polysialylation of the neural cell adhesion molecule ( NCAM ) is catalyzed by two polysialyltransferases , ST8Sia 2 ( STX ) and ST8Sia 4 ( PST ) , which contain sialylmotifs L and S conserved in all members of the sialyltransferases . ^^^ To obtain insight into the structure / function of ST8Sia 4 , we expressed human ST8Sia 4 in insect cells , Trichoplusia ni , and found that the enzyme produced in the insect cells catalyzes NCAM polysialylation , although it can not polysialylate itself ( `` autopolysialylation ' ' ) . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| In neural development , the function of NCAM is modified by polysialylation catalyzed by two polysialyltransferases , ST8Sia 2 and ST8Sia 4 . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| However , even in the tumor cells negative for PSA , they expressed PSA after transfection of neural cell adhesion molecule ( NCAM ) cDNA when these cells expressed PST , suggesting that the presence of NCAM was critical for PSA expression . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Two enzymes , the alpha 2 , 8 polysialyltransferases ST8Sia 4 ( ) / PST and ST8Sia 2 ( ) / STX are responsible for the polysialylation of NCAM . ^^^ Therefore , we conclude that autopolysialylation of ST8Sia II / STX , like that of ST8Sia IV / PST , is not required for , but does enhance , NCAM polysialylation . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Two closely related polysialyltransferases , ST8Sia 2 ( STX ) and ST8Sia 4 ( PST ) have been cloned previously and shown to synthesize polysialic acid on NCAM and other glycoproteins . ^^^ Moreover , ST8Sia 4 is responsible for the polysialylation of NCAM in oligodendrocytes . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Two polysialyltransferases , ST8Sia 2 and ST8Sia 4 , play dominant roles in polysialic acid synthesis on NCAM . ^^^ Previous studies indicate that ST8Sia 4 forms more highly polysialylated N glycans on NCAM than ST8Sia 2 in vitro . ^^^ In the present study , we first demonstrated that a combination of ST8Sia 2 and ST8Sia 4 cooperatively polysialylated NCAM , resulting in NCAM N glycans containing more , and thus longer , polysialic acid than when the enzymes were used individually . ^^^ There was also an increase in polysialylated NCAM when we used ST8Sia 2 and ST8Sia 4 sequentially , whereas there appeared to be a subtle increase when the enzymes were used in the reverse order . ^^^ Furthermore , ST8Sia 4 was able to add polysialic acid to oligosialylated oligosaccharides and unpolysialylated antennas in N glycans attached to NCAM , even when polysialic acid was attached to at least one of the other antennas . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Polysialylation of NCAM is catalyzed by two polysialyltransferases , ST8Sia 2 ( STX ) and ST8Sia 4 ( PST ) , which belong to the family of six genes encoding alpha 2 , 8 sialyltransferases . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| NCAM polysialylation can occur via either of two specific sialyltransferases , ST8SiaII ( STX ) and ST8SiaIV ( PST ) , and the purpose of this study was to determine if retroviral delivery of either PST or STX could induce PSA expression in vivo and thereby alter tissue plasticity . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Two highly homologous polysialyltransferases , ST8Sia 2 and ST8Sia 4 , which belong to the sialyltransferase gene family , synthesize polysialic acid on NCAM . ^^^ By contrast , ST8Sia 3 , which is moderately homologous to ST8Sia 2 and ST8Sia 4 , adds oligosialic acid to itself but very inefficiently to NCAM . ^^^ Here , we report domains of polysialyltransferases required for NCAM recognition and polysialylation by generating chimeric enzymes between ST8Sia 4 and ST8Sia 3 or ST8Sia 2 . ^^^ To identify domains responsible for NCAM polysialylation , different segments of the ST8Sia 4 catalytic domain , identified by the deletion experiments , were replaced with corresponding segments of ST8Sia 2 and ST8Sia 3 . ^^^ However , chimeric enzymes that contain only the carboxyl terminal segment of ST8Sia 4 and the amino terminal segment of ST8Sia 3 showed very weak activity toward NCAM , even though they had strong activity in polysialylating themselves . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Approaches to discover PSA function have involved the application of endoneuraminidase N to remove PSA and genetic manipulations in the mouse to deplete either NCAM or ST8Sia 4 . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| Two enzymes , the polysialyltransferases ST8SiaIV and ST8SiaII , are known to be involved in the polysialylation of NCAM . ^^^ Our data indicate that increased expression of ST8SiaIV enables accelerated polysialylation of NCAM , which might be coupled to a loss of adhesive functions of tumor cells . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| The polysialyltransferases [ ST8SiaIV ( PST 1 ) and ST8SiaII ] are responsible for the addition of polysialic acid ( PSA ) to NCAM . ^^^ It is interesting that overexpression of the PPARdelta but not PPARalpha or PPARgamma in F 9 cells resulted in higher induction of NCAM mRNA and protein expression and of PST 1 mRNA expression ( and a higher PSA level ) than in mock transfected F 9 cells . ^^^ We conclude that NCAM and PST 1 are molecular markers in F 9 cell differentiation caused by treatment with teratogenic VPA compounds or TSA and suggest that in addition to HDAC inhibition PPARdelta is involved in the signaling pathway . . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| The potential of this new method was evaluated using a nonpolysialylated construct of N CAM that was polysialylated in vitro using a soluble construct of ST8Sia 2 or ST8Sia 4 . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| To dissect polySia and NCAM functions , we generated polySia negative but NCAM positive mice by simultaneous deletion of the two polysialyltransferase genes , St8sia 2 and St8sia 4 . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| We show that basal synaptic transmission , measured as the slope of field excitatory postsynaptic potentials , was reduced strongly in mice lacking ST8SiaII / STX , the enzyme involved in polysialylation of NCAM in stem cell derived immature granule cells , but not in mice deficient either in the NCAM glycoprotein or the enzyme ST8SiaIV / PST involved in polysialylation of NCAM in mature neurons . ^^^ Strikingly , only mice deficient in NCAM , but not in PST or STX , were impaired in long term potentiation ( LTP ) induced by theta burst stimulation , suggesting that LTP in the dentate gyrus depends on the NCAM glycoprotein alone rather than on its associated PSA . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| BACKGROUND : Sialyltransferase 8B ( SIAT8B ) and 8D ( SIAT8D ) are two polysialyltransferases that catalyze the transfer of polysialic acid ( PSA ) to the neural cell adhesion molecule 1 ( NCAM 1 ) . ^^^ |
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| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| NA |
|
| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| NA |
|
| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| NA |
|
| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| NA |
|
| Interacting proteins: P13591 and Q92187 |
Pubmed |
SVM Score :0.0 |
| NA |
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