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Spinophilin participates in information transfer at immunological synapses.

Bloom O, Unternaehrer JJ, Jiang A, Shin JS, Delamarre L, Allen P, Mellman I - J. Cell Biol. (2008)

Bottom Line: In DCs interacting with T cells, spinophilin is polarized dynamically to contact sites in an antigen-dependent manner.It is also required for optimal T cell activation because DCs derived from mice lacking spinophilin exhibit defects in antigen presentation both in vitro and in vivo.Thus, spinophilin may play analogous roles in information transfer at both neuronal and immunological synapses.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Ludwig Institute for Cancer Research, New Haven, CT 06520, USA.

ABSTRACT
The adaptive immune response is initiated by the presentation of peptides bound to major histocompatibility complex molecules on dendritic cells (DCs) to antigen-specific T lymphocytes at a junction termed the immunological synapse. Although much attention has been paid to cytoplasmic events on the T cell side of the synapse, little is known concerning events on the DC side. We have sought signal transduction components of the neuronal synapse that were also expressed by DCs. One such protein is spinophilin, a scaffolding protein of neuronal dendritic spines that regulates synaptic transmission. In inactive, immature DCs, spinophilin is located throughout the cytoplasm but redistributes to the plasma membrane upon stimulus-induced maturation. In DCs interacting with T cells, spinophilin is polarized dynamically to contact sites in an antigen-dependent manner. It is also required for optimal T cell activation because DCs derived from mice lacking spinophilin exhibit defects in antigen presentation both in vitro and in vivo. Thus, spinophilin may play analogous roles in information transfer at both neuronal and immunological synapses.

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Spinophilin is recruited to the IS. (a and b) DCs (day six) were cocultured in the presence (+Antigen) or absence (−Antigen) of agonist peptide (MCC; a and b, respectively) and splenic CD4+ T cells. Confocal sections along the z axis of conjugated cells are shown in a and b. (a) In the presence of an antigen, topographical distribution of spinophilin (red), MHCII (green), and CD3, a component of the TCR (Cy5), reveals the polarization of spinophilin on the DC toward activated T cells. (b) In the absence of antigen, spinophilin remains localized close to the plasma membrane, as seen in mature DCs cultured in the absence of T cells (Fig. 1). Bar, 5 μm. (c) Correlation of spinophilin polarization in DCs with TCR clustering within T cells. Within DCs, the polarization of spinophilin toward contacting T cells correlated with TCR clustering to the contact site but not with MHCII. Error bars indicate the SEM.
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fig2: Spinophilin is recruited to the IS. (a and b) DCs (day six) were cocultured in the presence (+Antigen) or absence (−Antigen) of agonist peptide (MCC; a and b, respectively) and splenic CD4+ T cells. Confocal sections along the z axis of conjugated cells are shown in a and b. (a) In the presence of an antigen, topographical distribution of spinophilin (red), MHCII (green), and CD3, a component of the TCR (Cy5), reveals the polarization of spinophilin on the DC toward activated T cells. (b) In the absence of antigen, spinophilin remains localized close to the plasma membrane, as seen in mature DCs cultured in the absence of T cells (Fig. 1). Bar, 5 μm. (c) Correlation of spinophilin polarization in DCs with TCR clustering within T cells. Within DCs, the polarization of spinophilin toward contacting T cells correlated with TCR clustering to the contact site but not with MHCII. Error bars indicate the SEM.

Mentions: Because spinophilin is enriched at neuronal synapses, we wondered if it was similarly localized to the IS and, if so, whether its localization correlated with T cell activation. We cocultured mature DCs (B10 or C57BL/6) with antigen-specific T cells (AND or OT-II, respectively) in the presence or absence of an agonist peptide (moth cytochrome c aa 88–103 or ovalbumin aa 323–339). After 20 min, cells were fixed and stained for spinophilin, MHCII, and the TCR (CD3). A portion of conjugates were found to have spinophilin polarized toward the T cell. Strikingly, the polarization of spinophilin within a DC toward a T cell coincided almost exclusively with clustered TCR on the T cell (Fig. 2, a and c). In contrast, MHCII was rarely polarized toward a T cell in a pattern overlapping with spinophilin (n = 48 conjugates total; Fig. 2, a and c), indicating that the recruitment of spinophilin toward contact sites did not simply reflect an accumulation or ruffling of bulk DC membrane. As shown previously, the presence of an antigen increased TCR enrichment at contacts nearly twofold (unpublished data; Revy et al., 2001). In conjugates without TCR clustering (and without antigen), spinophilin was found in the cytosol and in close apposition to the plasma membrane, as observed in mature DCs cultured without T cells (Fig. 2 b).


Spinophilin participates in information transfer at immunological synapses.

Bloom O, Unternaehrer JJ, Jiang A, Shin JS, Delamarre L, Allen P, Mellman I - J. Cell Biol. (2008)

Spinophilin is recruited to the IS. (a and b) DCs (day six) were cocultured in the presence (+Antigen) or absence (−Antigen) of agonist peptide (MCC; a and b, respectively) and splenic CD4+ T cells. Confocal sections along the z axis of conjugated cells are shown in a and b. (a) In the presence of an antigen, topographical distribution of spinophilin (red), MHCII (green), and CD3, a component of the TCR (Cy5), reveals the polarization of spinophilin on the DC toward activated T cells. (b) In the absence of antigen, spinophilin remains localized close to the plasma membrane, as seen in mature DCs cultured in the absence of T cells (Fig. 1). Bar, 5 μm. (c) Correlation of spinophilin polarization in DCs with TCR clustering within T cells. Within DCs, the polarization of spinophilin toward contacting T cells correlated with TCR clustering to the contact site but not with MHCII. Error bars indicate the SEM.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2315669&req=5

fig2: Spinophilin is recruited to the IS. (a and b) DCs (day six) were cocultured in the presence (+Antigen) or absence (−Antigen) of agonist peptide (MCC; a and b, respectively) and splenic CD4+ T cells. Confocal sections along the z axis of conjugated cells are shown in a and b. (a) In the presence of an antigen, topographical distribution of spinophilin (red), MHCII (green), and CD3, a component of the TCR (Cy5), reveals the polarization of spinophilin on the DC toward activated T cells. (b) In the absence of antigen, spinophilin remains localized close to the plasma membrane, as seen in mature DCs cultured in the absence of T cells (Fig. 1). Bar, 5 μm. (c) Correlation of spinophilin polarization in DCs with TCR clustering within T cells. Within DCs, the polarization of spinophilin toward contacting T cells correlated with TCR clustering to the contact site but not with MHCII. Error bars indicate the SEM.
Mentions: Because spinophilin is enriched at neuronal synapses, we wondered if it was similarly localized to the IS and, if so, whether its localization correlated with T cell activation. We cocultured mature DCs (B10 or C57BL/6) with antigen-specific T cells (AND or OT-II, respectively) in the presence or absence of an agonist peptide (moth cytochrome c aa 88–103 or ovalbumin aa 323–339). After 20 min, cells were fixed and stained for spinophilin, MHCII, and the TCR (CD3). A portion of conjugates were found to have spinophilin polarized toward the T cell. Strikingly, the polarization of spinophilin within a DC toward a T cell coincided almost exclusively with clustered TCR on the T cell (Fig. 2, a and c). In contrast, MHCII was rarely polarized toward a T cell in a pattern overlapping with spinophilin (n = 48 conjugates total; Fig. 2, a and c), indicating that the recruitment of spinophilin toward contact sites did not simply reflect an accumulation or ruffling of bulk DC membrane. As shown previously, the presence of an antigen increased TCR enrichment at contacts nearly twofold (unpublished data; Revy et al., 2001). In conjugates without TCR clustering (and without antigen), spinophilin was found in the cytosol and in close apposition to the plasma membrane, as observed in mature DCs cultured without T cells (Fig. 2 b).

Bottom Line: In DCs interacting with T cells, spinophilin is polarized dynamically to contact sites in an antigen-dependent manner.It is also required for optimal T cell activation because DCs derived from mice lacking spinophilin exhibit defects in antigen presentation both in vitro and in vivo.Thus, spinophilin may play analogous roles in information transfer at both neuronal and immunological synapses.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Ludwig Institute for Cancer Research, New Haven, CT 06520, USA.

ABSTRACT
The adaptive immune response is initiated by the presentation of peptides bound to major histocompatibility complex molecules on dendritic cells (DCs) to antigen-specific T lymphocytes at a junction termed the immunological synapse. Although much attention has been paid to cytoplasmic events on the T cell side of the synapse, little is known concerning events on the DC side. We have sought signal transduction components of the neuronal synapse that were also expressed by DCs. One such protein is spinophilin, a scaffolding protein of neuronal dendritic spines that regulates synaptic transmission. In inactive, immature DCs, spinophilin is located throughout the cytoplasm but redistributes to the plasma membrane upon stimulus-induced maturation. In DCs interacting with T cells, spinophilin is polarized dynamically to contact sites in an antigen-dependent manner. It is also required for optimal T cell activation because DCs derived from mice lacking spinophilin exhibit defects in antigen presentation both in vitro and in vivo. Thus, spinophilin may play analogous roles in information transfer at both neuronal and immunological synapses.

Show MeSH
Related in: MedlinePlus