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Reim D, Weis TM, Halbedl S, Delling JP, Grabrucker AM, Boeckers TM, Schmeisser MJ. The Shank3 Interaction Partner ProSAPiP1 Regulates Postsynaptic SPAR Levels and the Maturation of Dendritic Spines in Hippocampal Neurons. Front Synaptic Neurosci 2016; 8:13. [PMID: 27252646 PMCID: PMC4877498 DOI: 10.3389/fnsyn.2016.00013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/10/2016] [Indexed: 11/13/2022] Open
Abstract
The postsynaptic density or PSD is a submembranous compartment containing a wide array of proteins that contribute to both morphology and function of excitatory glutamatergic synapses. In this study, we have analyzed functional aspects of the Fezzin ProSAP-interacting protein 1 (ProSAPiP1), an interaction partner of the well-known PSD proteins Shank3 and SPAR. Using lentiviral-mediated overexpression and knockdown of ProSAPiP1, we found that this protein is dispensable for the formation of both pre- and postsynaptic specializations per se. We further show that ProSAPiP1 regulates SPAR levels at the PSD and the maturation of dendritic spines. In line with previous findings on the ProSAPiP1 homolog PSD-Zip70, we conclude that Fezzins essentially contribute to the maturation of excitatory spine synapses.
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Affiliation(s)
- Dominik Reim
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; International Graduate School in Molecular Medicine, Ulm UniversityUlm, Germany
| | - Tobias M Weis
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; International Graduate School in Molecular Medicine, Ulm UniversityUlm, Germany
| | - Sonja Halbedl
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; International Graduate School in Molecular Medicine, Ulm UniversityUlm, Germany
| | - Jan Philipp Delling
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; International Graduate School in Molecular Medicine, Ulm UniversityUlm, Germany
| | - Andreas M Grabrucker
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; WG Molecular Analysis of Synaptopathies, Department of Neurology, Neurocenter of Ulm UniversityUlm, Germany
| | | | - Michael J Schmeisser
- Institute for Anatomy and Cell Biology, Ulm UniversityUlm, Germany; Department of Neurology, Ulm UniversityUlm, Germany
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Dolnik A, Kanwal N, Mackert S, Halbedl S, Proepper C, Bockmann J, Schoen M, Boeckers TM, Kühl SJ, Schmeisser MJ. Sipa1l3/SPAR3 is targeted to postsynaptic specializations and interacts with the Fezzin ProSAPiP1/Lzts3. J Neurochem 2015; 136:28-35. [PMID: 26364583 DOI: 10.1111/jnc.13353] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 08/10/2015] [Accepted: 09/01/2015] [Indexed: 12/01/2022]
Abstract
Rap GTPase-activating proteins (RapGAPs) are essential for synaptic function as they tightly regulate synaptic Rap signaling. Among the most abundant synaptic RapGAPs in brain are the Spine-associated RapGAPs (SPARs) Sipa1l1/SPAR and Sipa1l2/SPAR2, whereas nothing has been reported on Sipa1l3/SPAR3. In this study, we show that Sipa1l3/SPAR3 is conserved across species, has a distinct expression pattern in the developing rat brain and is localized at excitatory postsynapses. We further demonstrate that the Sipa1l3/SPAR3 C-terminus is required for postsynaptic targeting and represents an interaction module for Fezzins such as ProSAPiP1/Lzts3, a binding partner of the postsynaptic scaffold protein Shank3. Taken together, our data imply that Sipa1l3/SPAR3 is a hitherto unknown synaptic RapGAP, which is targeted to postsynaptic specializations and interacts with Fezzins. Spine-associated RapGAPs (SPARs) are essential modulators of synaptic signaling. Our study is the first to characterize the SPAR family member Sipa1l3/SPAR3 in neuronal tissue. We show that Sipa1l3/SPAR3 is conserved across species, has a distinct expression pattern in brain and is localized to excitatory postsynapses via its C-terminus, which represents an interaction module for other postsynaptic proteins including the Fezzin ProSAPiP1/Lzts3.
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Affiliation(s)
- Anna Dolnik
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Noreen Kanwal
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,International Graduate School in Molecular Medicine Ulm, IGradU, Ulm University, Ulm, Germany
| | - Sarah Mackert
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,International Graduate School in Molecular Medicine Ulm, IGradU, Ulm University, Ulm, Germany
| | - Sonja Halbedl
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,International Graduate School in Molecular Medicine Ulm, IGradU, Ulm University, Ulm, Germany
| | | | - Juergen Bockmann
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Michael Schoen
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Susanne J Kühl
- Institute for Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Michael J Schmeisser
- Institute for Anatomy and Cell Biology, Ulm University, Ulm, Germany.,Department of Neurology, Ulm University, Ulm, Germany
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