A Human STX cDNA Confers Polysialic Acid Expression in Mammalian Cells

Scheidegger, E. Paul; Sternberg, Lawrence R.; Roth, Jürgen; Lowe, John B.

doi:10.1074/jbc.270.39.22685

Cited by 138 publications

(65 citation statements)

References 36 publications

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“…In mammals, ST8Sia polysialyltransferases (polySTs) are type II membrane proteins that reside in the Golgi. Two human polyST members have been characterized, ST8Sia-II and ST8Sia-IV (21,22), and are responsible for the polysialylation of NCAM. PolySTs are themselves modified by autopolysialylation with α2,8-linked polysialic acid chains (23).…”

Section: Human Polysialyltransferases Are Functional When Transientlymentioning

confidence: 99%

Engineering of complex protein sialylation in plants

Kallolimath

Castilho

Strasser

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Sialic acids (Sias) are abundant terminal modifications of protein-linked glycans. A unique feature of Sia, compared with other monosaccharides, is the formation of linear homo-polymers, with its most complex form polysialic acid (polySia). Sia and polySia mediate diverse biological functions and have great potential for therapeutic use. However, technological hurdles in producing defined protein sialylation due to the enormous structural diversity render their precise investigation a challenge. Here, we describe a plant-based expression platform that enables the controlled in vivo synthesis of sialylated structures with different interlinkages and degree of polymerization (DP). The approach relies on a combination of stably transformed plants with transient expression modules. By the introduction of multigene vectors carrying the human sialylation pathway into glycosylation-destructed mutants, transgenic plants that sialylate glycoproteins in α2,6- or α2,3-linkage were generated. Moreover, by the transient coexpression of human α2,8-polysialyltransferases, polySia structures with a DP >40 were synthesized in these plants. Importantly, plant-derived polySia are functionally active, as demonstrated by a cell-based cytotoxicity assay and inhibition of microglia activation. This pathway engineering approach enables experimental investigations of defined sialylation and facilitates a rational design of glycan structures with optimized biotechnological functions.

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Section: Human Polysialyltransferases Are Functional When Transientlymentioning

confidence: 99%

Engineering of complex protein sialylation in plants

Kallolimath

Castilho

Strasser

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Thus, mouse ST8Sia II specifically synthesizes PSA chains on the specific NCAM isoforms, especially in vivo. Transient transfection of the ST8Sia II/STX gene as well as the ST8Sia IV/PST-1 gene caused PSA expression on NCAM-negative cell lines such as COS-7 (15,26), but the expression of PSA associated with other proteins may be due to over-expression of the PSA synthase genes.…”

Section: Discussionmentioning

confidence: 99%

“…These observations suggest that ST8Sia II/STX rather than ST8Sia IV/PST-1 is involved in the biosynthesis of PSA associated with NCAM during mouse brain development. However, there is no evidence that the PSA on NCAM is specifically synthesized by ST8Sia II in vivo as well as in vitro, because PSA was synthesized on some glycoproteins such as fetuin in vitro (11), and the transfection of the human STX gene into NCAM-negative cells also caused the expression of PSA on the cell surface (15).…”

mentioning

confidence: 99%

Characterization of Mouse ST8Sia II (STX) as a Neural Cell Adhesion Molecule-specific Polysialic Acid Synthase

Kojima

Tachida

Yoshida

et al. 1996

Journal of Biological Chemistry

116

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Polysialic acid (PSA) 1 is an unusual carbohydrate associated with the neural cell adhesion molecule (NCAM) and the ␣-subunit of the voltage-gated sodium channel in mammals and is more abundant in embryonic than adult brain (1-3). PSA is implicated in the reduction of NCAM adhesion through its large negative charge and thereby allows increased neurite outgrowth and cell motility (4 -6). It is also reported that the presence of PSA affects cell-cell interactions through other adhesion molecules (7). Although functions of PSA have been described, little is known about the mechanisms by which the synthesis and expression of PSA are regulated.PSA on NCAM has so far been considered to be synthesized through the actions of at least two distinct enzymes, i.e. an initiator ␣2,8-sialyltransferase, which adds a single ␣2,8-linked sialic acid to ␣2,3-linked sialic acid residues on N-glycans, and a polysialyltransferase, which adds multiple ␣2,8-linked sialic acid residues (8). Livingston and Paulson (9) cloned STX/ST8Sia II, a new member of the sialyltransferase gene family from rat. Recently, we showed that ST8Sia II/STX cloned from mouse can synthesize PSA on ␣2,3-sialylated Nglycans of glycoproteins without an initiator ␣2,8-sialyltransferase in vitro and direct in vivo synthesis of PSA in several cells (10,11). In addition, we cloned mouse ST8Sia IV by homology cloning using the sequence information on GD3 synthase (12) and STX (9) and showed that the mouse enzyme can synthesize PSA, like ST8Sia II/STX (13). Eckhardt et al. (14) also cloned a sialyltransferase, which is involved in the biosynthesis of PSA on NCAM from hamster, namely PST-1. Hamster PST-1 showed 99.2% identity to mouse ST8Sia IV, indicating that the hamster enzyme is a counterpart of mouse ST8Sia IV. The gene expression of mouse ST8Sia II was restricted in the brain and was dramatically up-and down-regulated during developmental stages of the brain like the expression of PSA, whereas mouse ST8Sia IV was strongly expressed in lung and heart rather than brain, and only little regulation was observed during brain development (10, 13). These observations suggest that ST8Sia II/STX rather than ST8Sia IV/PST-1 is involved in the biosynthesis of PSA associated with NCAM during mouse brain development. However, there is no evidence that the PSA on NCAM is specifically synthesized by ST8Sia II in vivo as well as in vitro, because PSA was synthesized on some glycoproteins such as fetuin in vitro (11), and the transfection of the human STX gene into NCAM-negative cells also caused the expression of PSA on the cell surface (15).The present study focuses on the biosynthesis of PSA by mouse ST8Sia II using a recombinant soluble NCAM fused with the Fc region of human IgG1 (NCAM-Fc) and comparison of the activities of mouse ST8Sia II and IV. ST8Sia II specifically and directly synthesized PSA on ␣2,3-linked sialic acid residues of N-glycans of specific isoforms of NCAM, without

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“…In the adult brain, high levels of PSA-NCAM remain restricted to specific regions that either retain neurogenic capacity, such as the subventricular zone and the granular cell layer of the hippocampus, or that exhibit physiological plasticity, such as regions of the hypothalamus, the entorhinal-hippocampal complex and the thalamus (Bonfanti, 2006;Gascon, Vutskits, & Kiss, 2007;Rutishauser, 2008). PSA is synthesized by two polysialyltransferases ST8Sia-II/STX (Kojima et al, 1996;Scheidegger, Sternberg, Roth, & Lowe, 1995) and ST8SiaIV/PST (Eckhardt et al, 1995;Nakayama, Fukuda, Fredette, Ranscht, & Fukuda, 1995). Both polysialyltransferase mRNAs are coexpressed, but they differ markedly with respect to their spatial and temporal expression patterns.…”

Section: Ncam Polysialylation (Psa-ncam)mentioning

confidence: 99%

Learning under stress: A role for the neural cell adhesion molecule NCAM

Bisaz

Conboy

Sandi

2009

Neurobiology of Learning and Memory

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a b s t r a c tStress is known to be a potent modulator of brain function and cognition. While prolonged and/or excessive stress generally exerts negative effects on learning and memory processes, acute stress can have differential effects on memory function depending on a number of factors (such as stress duration, stress intensity, timing and the source of the stress, as well as the learning type under study). Here, we have focused on the effects of 'acute' stress, and examined the literature attending to whether the ''source of stress" is 'intrinsic' (i.e., when stress is originated by the cognitive task) or 'extrinsic' (i.e., when stress is induced by elements not related to the cognitive task). We have questioned here whether the neural cell adhesion molecule of the immunoglobulin superfamily (NCAM) contributes to the neurobiological mechanisms that translate the effects of these two different stress sources into the different behavioral and cognitive outcomes. NCAM is a cell adhesion macromolecule known to play a critical role in development and plasticity of the nervous system. NCAM and its post-translational modified form PSA-NCAM are critically involved in mechanisms of learning and memory and their expression levels are known to be highly susceptible to modulation by stress. Whereas available data are insufficient to conclude as to whether NCAM mediates extrinsic stress effects on learning and memory processes, we present systematic evidence supporting a key mediating role for both NCAM and PSA-NCAM in the facilitation of memory consolidation induced by intrinsic stress. Furthermore, NCAM is suggested to participate in some of the bidirectional effects of stress on memory processes, with its enhanced synaptic expression involved in facilitating stress actions while its reduced expression being related to impairing effects of stress on memory function.

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A Human STX cDNA Confers Polysialic Acid Expression in Mammalian Cells

Cited by 138 publications

References 36 publications

Engineering of complex protein sialylation in plants

Engineering of complex protein sialylation in plants

Characterization of Mouse ST8Sia II (STX) as a Neural Cell Adhesion Molecule-specific Polysialic Acid Synthase

Learning under stress: A role for the neural cell adhesion molecule NCAM

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