Swiprosin-1/EFhd2 controls B cell receptor signaling through the assembly of the B cell receptor, Syk, and phospholipase C gamma2 in membrane rafts.
Compartmentalization of the BCR in membrane rafts is important for its signaling capacity. Swiprosin-1/EFhd2 (Swip-1) is an EF-hand and coiled-coil-containing adaptor protein with predicted Src homology 3 (SH3) binding sites that we identified in membrane rafts. We showed previously that Swip-1 ampl...
| Main Authors: | , , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
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2010
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| _version_ | 1797065221578162176 |
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| author | Kroczek, C Lang, C Brachs, S Grohmann, M Dütting, S Schweizer, A Nitschke, L Feller, S Jäck, H Mielenz, D |
| author_facet | Kroczek, C Lang, C Brachs, S Grohmann, M Dütting, S Schweizer, A Nitschke, L Feller, S Jäck, H Mielenz, D |
| author_sort | Kroczek, C |
| collection | OXFORD |
| description | Compartmentalization of the BCR in membrane rafts is important for its signaling capacity. Swiprosin-1/EFhd2 (Swip-1) is an EF-hand and coiled-coil-containing adaptor protein with predicted Src homology 3 (SH3) binding sites that we identified in membrane rafts. We showed previously that Swip-1 amplifies BCR-induced apoptosis; however, the mechanism of this amplification was unknown. To address this question, we overexpressed Swip-1 and found that Swip-1 amplified the BCR-induced calcium flux in WEHI231, B62.1, and Bal17 cells. Conversely, the BCR-elicited calcium flux was strongly attenuated in Swip-1-silenced WEHI231 cells, and this was due to a decreased calcium mobilization from intracellular stores. Complementation of Swip-1 expression in Swip-1-silenced WEHI231 cells restored the BCR-induced calcium flux and enhanced spleen tyrosine kinase (Syk) tyrosine phosphorylation and activity as well as SLP65/BLNK/BASH and phospholipase C gamma2 (PLCgamma2) tyrosine phosphorylation. Furthermore, Swip-1 induced the constitutive association of the BCR itself, Syk, and PLCgamma2 with membrane rafts. Concomitantly, Swip-1 stabilized the association of BCR with tyrosine-phosphorylated proteins, specifically Syk and PLCgamma2, and enhanced the constitutive interaction of Syk and PLCgamma2 with Lyn. Interestingly, Swip-1 bound to the rSH3 domains of the Src kinases Lyn and Fgr, as well as to that of PLCgamma. Deletion of the predicted SH3-binding region in Swip-1 diminished its association and that of Syk and PLCgamma2 with membrane rafts, reduced its interaction with the SH3 domain of PLCgamma, and diminished the BCR-induced calcium flux. Hence, Swip-1 provides a membrane scaffold that is required for the Syk-, SLP-65-, and PLCgamma2-dependent BCR-induced calcium flux. |
| first_indexed | 2024-03-06T21:25:33Z |
| format | Journal article |
| id | oxford-uuid:42faa331-1fd2-4b60-a9fa-2ac64730dd3d |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T21:25:33Z |
| publishDate | 2010 |
| record_format | dspace |
| spelling | oxford-uuid:42faa331-1fd2-4b60-a9fa-2ac64730dd3d2022-03-26T14:52:38ZSwiprosin-1/EFhd2 controls B cell receptor signaling through the assembly of the B cell receptor, Syk, and phospholipase C gamma2 in membrane rafts.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:42faa331-1fd2-4b60-a9fa-2ac64730dd3dEnglishSymplectic Elements at Oxford2010Kroczek, CLang, CBrachs, SGrohmann, MDütting, SSchweizer, ANitschke, LFeller, SJäck, HMielenz, DCompartmentalization of the BCR in membrane rafts is important for its signaling capacity. Swiprosin-1/EFhd2 (Swip-1) is an EF-hand and coiled-coil-containing adaptor protein with predicted Src homology 3 (SH3) binding sites that we identified in membrane rafts. We showed previously that Swip-1 amplifies BCR-induced apoptosis; however, the mechanism of this amplification was unknown. To address this question, we overexpressed Swip-1 and found that Swip-1 amplified the BCR-induced calcium flux in WEHI231, B62.1, and Bal17 cells. Conversely, the BCR-elicited calcium flux was strongly attenuated in Swip-1-silenced WEHI231 cells, and this was due to a decreased calcium mobilization from intracellular stores. Complementation of Swip-1 expression in Swip-1-silenced WEHI231 cells restored the BCR-induced calcium flux and enhanced spleen tyrosine kinase (Syk) tyrosine phosphorylation and activity as well as SLP65/BLNK/BASH and phospholipase C gamma2 (PLCgamma2) tyrosine phosphorylation. Furthermore, Swip-1 induced the constitutive association of the BCR itself, Syk, and PLCgamma2 with membrane rafts. Concomitantly, Swip-1 stabilized the association of BCR with tyrosine-phosphorylated proteins, specifically Syk and PLCgamma2, and enhanced the constitutive interaction of Syk and PLCgamma2 with Lyn. Interestingly, Swip-1 bound to the rSH3 domains of the Src kinases Lyn and Fgr, as well as to that of PLCgamma. Deletion of the predicted SH3-binding region in Swip-1 diminished its association and that of Syk and PLCgamma2 with membrane rafts, reduced its interaction with the SH3 domain of PLCgamma, and diminished the BCR-induced calcium flux. Hence, Swip-1 provides a membrane scaffold that is required for the Syk-, SLP-65-, and PLCgamma2-dependent BCR-induced calcium flux. |
| spellingShingle | Kroczek, C Lang, C Brachs, S Grohmann, M Dütting, S Schweizer, A Nitschke, L Feller, S Jäck, H Mielenz, D Swiprosin-1/EFhd2 controls B cell receptor signaling through the assembly of the B cell receptor, Syk, and phospholipase C gamma2 in membrane rafts. |
| title | Swiprosin-1/EFhd2 controls B cell receptor signaling through the assembly of the B cell receptor, Syk, and phospholipase C gamma2 in membrane rafts. |
| title_full | Swiprosin-1/EFhd2 controls B cell receptor signaling through the assembly of the B cell receptor, Syk, and phospholipase C gamma2 in membrane rafts. |
| title_fullStr | Swiprosin-1/EFhd2 controls B cell receptor signaling through the assembly of the B cell receptor, Syk, and phospholipase C gamma2 in membrane rafts. |
| title_full_unstemmed | Swiprosin-1/EFhd2 controls B cell receptor signaling through the assembly of the B cell receptor, Syk, and phospholipase C gamma2 in membrane rafts. |
| title_short | Swiprosin-1/EFhd2 controls B cell receptor signaling through the assembly of the B cell receptor, Syk, and phospholipase C gamma2 in membrane rafts. |
| title_sort | swiprosin 1 efhd2 controls b cell receptor signaling through the assembly of the b cell receptor syk and phospholipase c gamma2 in membrane rafts |
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