Forschung
Research focus
The work of our group focuses on the molecular and functional characterization of tonically active ribbon synapses in the retina.
Ribbon synapses are specialized for continuous synaptic transmission but are also capable of fast, stimulus-synchronous phasic responses. The function of ribbon synapses with their phasic and continuous mode of transmission is essential for retinal physiology and important for visual information processing. Mutations of genes involved in signaling at ribbon synapses, particularly at photoreceptor ribbon synapses, lead to retinal diseases that can result into blindness. We address the function of retinal ribbon synapses at the molecular, cellular and systems level.
Papadopoulos S, Tinschert R, Papadopoulos I, Gerloff X, Schmitz F. (2024)
Analytical Post-Embedding Immunogold-Electron Microscopy with Direct Gold-Labelled Monoclonal Primary Antibodies against RIBEYE A- and B-Domain Suggests a Refined Model of Synaptic Ribbon Assembly.
Int. J. Mol. Sci. 2024, 25(13), 7443;
https://doi.org/10.3390/ijms25137443
Martus D, Williams SK, Pichi K, Mannebach-Götz S, Kaiser N, Wardas B, Fecher-Trost C, Meyer MR, Schmitz F, Beck A, Fairless R, Diem R, Flockerzi V, Belkacemi A (2024)Cavβ3 Contributes to the Maintenance of the Blood-Brain Barrier and Alleviates Symptoms of Experimental Autoimmune Encephalitis.
Arterioscler Thromb Vasc Biol. 2024 Jul 3.
https://www.ahajournals.org/doi/10.1161/ATVBAHA.124.321141
Suiwal S, Wartenberg P, Boehm U, Schmitz F, Schwarz K (2024)
A novel Cre recombinase mouse strain for cell-specific deletion of floxed genes in ribbon synapse-forming retinal neurons.
Int. J. Mol. Sci. 2024, 25(3), 1916
https://www.mdpi.com/1422-0067/25/3/1916
Dittrich A, Ramesh G, Jung M, Schmitz F (2023)
Rabconnectin-3α/DMXL2 Is Locally Enriched at the Synaptic Ribbon of Rod Photoreceptor Synapses
Cells 12(12), 1665.
https://www.mdpi.com/2073-4409/12/12/1665
Schwarz K, Schmitz F (2023)
Synapse dysfunctions in multiple sclerosis
Int. J. Mol. Sci. 24(2), 1639.
https://www.mdpi.com/1422-0067/24/2/1639
Suiwal S, Dembla M, Schwarz K, Katiyar R, Jung M, Carius Y, Maxeiner S, Lauterbach MA, Lancaster CRD, Schmitz F.
Ciliary Proteins Repurposed by the Synaptic Ribbon: Trafficking Myristoylated Proteins at Rod Photoreceptor Synapses.
International Journal of Molecular Sciences. 2022; 23(13):7135.
https://doi.org/10.3390/ijms23137135
Shankhwar S, Schwarz K, Katiyar R, Jung M, Maxeiner S, Südhof TC, Schmitz F (2022)
RIBEYE B-Domain Is Essential for RIBEYE A-Domain Stability and Assembly of Synaptic Ribbons
Frontiers in Molecular Neuroscience 15, 838311
https://www.frontiersin.org/articles/10.3389/fnmol.2022.838311/full
Mukherjee A, Katiyar R, Dembla E, Dembla M, Kumar P, Belkacemi A, Jung M, Beck A, Flockerzi V, Schwarz K, Schmitz F (2020)
Disturbed presynaptic Ca2+ signaling in photoreceptors in the EAE mouse model of multiple sclerosis
iScience 23(12), 101830
DOI:https://doi.org/10.1016/j.isci.2020.101830
https://www.mdpi.com/1422-0067/22/19/10789
Kesharwani A, Schwarz K, Dembla E, Dembla M, Schmitz F (2021)
Early Changes in Exo- and Endocytosis in the EAE Mouse model of multiple sclerosis correlate with decreased synaptic ribbon size and reduced ribbon-associated vesicle pools in rod photoreceptor synapses
Int. J. Mol. Sci, 221, 789.
https://www.mdpi.com/journal/ijms/special_issues/ribbon_synapses
Fairless R, Williams SK, Katiyar R, Maxeiner S, Schmitz F, Diem R. (2020)
ERG responses in mice with deletion of the synaptic ribbon component RIBEYE
Invest Ophthalmol Vis Sci. 2020 May 11;61(5):37. doi: 10.1167/iovs.61.5.37.
https://iovs.arvojournals.org/article.aspx?articleid=2766228
Dembla E, Dembla M, Maxeiner S, Schmitz F (2020)
Synaptic ribbons foster active zone stability and illumination-dependent active zone enrichment of RIM2 and Cav1.4 in photoreceptor synapses
Scientific reports 10, 5957 (2020)
https://www.nature.com/articles/s41598-020-62734-0
Moser T, Grabner CP, Schmitz F (2019)
Sensory processing at ribbon synapses in the retina and the cochlea
Physiol Rev. 100(1),103-144
https://www.physiology.org/doi/abs/10.1152/physrev.00026.2018
Okawa H, Yu WQ, Matti U, Schwarz K, Odermatt B, Zhong H, Tsukamoto Y, Lagnado L, Rieke F, Schmitz F, Wong RO (2019)
Dynamic assembly of ribbon synapses and circuit maintenance in a vertebrate sensory system.
Nature Communications (2019) 10, 2167; 10.1038/s41467-019-10123-1
https://www.nature.com/articles/s41467-019-10123-1#Ack1
Favaro PD, Huang X, Hosang L, Stodieck S, Cui L, Liu YZ, Engelhardt KA, Schmitz F, Dong Y, Löwel S, Schlüter OM (2018)
An opposing function in paralogs in balancing developmental synapse maturation
PLoS Biol. 2018 Dec 26;16(12):e2006838. doi: 10.1371/journal.pbio.2006838.
https://www.ncbi.nlm.nih.gov/pubmed/30586380
Yu WQ, El-Danaf RN, Okawa H, Pacholec JM, Matti U, Schwarz K, Odermatt B, Dunn FA, Lagnado L, Schmitz F, Huberman AD, Wong ROL (2018)
Synaptic convergence patterns onto retinal ganglion cells are preserved despite topographic variation in pre- and postsynaptic territories.
Cell Rep.25, 2017-2026
https://www.cell.com/cell-reports/fulltext/S2211-1247(18)31693-0
Mayur Dembla, Ajay Kesharwani, Sivaraman Natarajan, Claudia Fecher‐Trost, Richard Fairless, Sarah K Williams, Veit Flockerzi, Ricarda Diem, Karin Schwarz, Frank Schmitz (2018)
Early auto‐immune targeting of photoreceptor ribbon synapses in mouse models of multiple sclerosis
EMBO Molecular Medicine e8926 DOI 10.15252/emmm.201808926 | Published online 28.09.2018
http://embomolmed.embopress.org/content/early/2018/09/28/emmm.201808926
Schwarz K, Schmitz F (2017)
Dysfunctional neuronal synapses in multiple sclerosis
Current Trends in Neurology 11, 1-13
http://www.researchtrends.net/tia/title_issue.asp?id=47&in=0&vn=11&type=3
Eich ML*, Dembla E*, Wahl S, Dembla M, Schwarz K, Schmitz F* (2017)
The calcineurin-binding, activity-dependent splice variant dynamin1xb is highly enriched in synapses in various regions of the central nervous system.
Frontiers in Molecular Neuroscience 10, 230.
http://journal.frontiersin.org/article/10.3389/fnmol.2017.00230/full
Karin Schwarz, Frank Schmitz (2017)
RIBEYE(B)-domain binds to lipid components of synaptic vesicles in an NAD(H)-dependent, redox-sensitive manner.
Biochem. J., epub ahead of print. pii: BCJ20160886. doi: 10.1042/BCJ20160886.
https://www.ncbi.nlm.nih.gov/pubmed/28202712
Shweta Suiwal, Gabriele Kiefer, Frank Schmitz, Karin Schwarz (2017)
An easy, fast and “low-tech”-equipment-requiring alternative method to optimize immunolabelling conditions for pre-embedding immunogold electron microscopy and to correlate light and electron microscopical immunogold labelling results.
Journal of Immunological Methods, epub ahead of print.
http://dx.doi.org/10.1016/j.jim.2017.02.003
StephanMaxeiner*, FujunLuo*, AlisonTan, FrankSchmitz, Thomas CSüdhof§ (2016)
How to make a synaptic ribbon: RIBEYE deletion abolishes ribbons in retinal synapses and disrupts neurotransmitter release.
EMBO J. 2016 Feb 29. pii: e201592701. [Epub ahead of print]
http://www.ncbi.nlm.nih.gov/pubmed/2692901
Wahl S*, Magupalli VG*, Dembla M*, Katiyar R*, Schwarz K*, Köblitz L, Alpadi K, Krause E, Rettig J, Sung C-H., Goldberg AFX, Schmitz F (2016)
The Disease Protein Tulp1 Is Essential for Periactive Zone Endocytosis in Photoreceptor Ribbon Synapses
Journal of Neuroscience 36(8): 2473-2493; doi: 10.1523/JNEUROSCI.2275-15.2016
* equal contributions
http://www.jneurosci.org/content/36/8/2473.short
Leon Lagnado and Frank Schmitz (2015)
Ribbon synapses and visual processing in the retina
Annual Review of Vision Science 1, 235-262.
http://www.annualreviews.org/toc/vision/1/1
Katiyar R*, Weissgerber P*, Roth E*, Dörr J, Sothilingam V, Garcia Garrido M, Beck SC, Seeliger M, Beck A, Schmitz F§, Flockerzi V§ (2015)
Influence of the β2-subunit of L-type voltage-gated Cav channels on the structural and functional development of photoreceptor ribbon synapses
*,§ equal contributions
Invest Ophthalmol Vis Sci. 2015 Mar 12. pii: IOVS-15-16654. doi: 10.1167/iovs.15-16654.
http://www.ncbi.nlm.nih.gov/pubmed/25766584
Anjum R, Ajoubian H, Schmitz F (2014)
Differential synaptic distribution of the scaffold proteins Cask and Caskin1 in the bovine retina
Mol Cell Neurosci 62, 19-29.
http://www.ncbi.nlm.nih.gov/pubmed/25123431
Mayur Dembla, Silke Wahl, Rashmi Katiyar, and Frank Schmitz
ArfGAP3 is a component of the photoreceptor synaptic ribbon complex and forms a NAD(H)-regulated, redox-sensitive complex with RIBEYE that is important for endocytosis
The Journal of Neuroscience,April 9, 2014.34(15):5245-5260
http://www.jneurosci.org/content/34/15/5245.full.pdf+html
Silke Wahl, Rashmi Katiyar and Frank Schmitz.
Fairless R, Williams SK, Hoffmann DB, Stojic A, Hochmeister S, Schmitz F, Storch MK, Diem R.
Preclinical retinal neurodegeneration in a model of multiple sclerosis.
J Neurosci. 2012 Apr 18;32(16):5585-97.
http://www.ncbi.nlm.nih.gov/pubmed/22393316
Grabner CP, Gandini MA, Rehak R, Le Y, Zamponi GW, Schmitz F.
RIM1/2-mediated facilitation of Cav1.4 channel opening is required for Ca2+-stimulated release in mouse rod photoreceptors.
J Neurosci. 2015 Sep 23;35(38):13133-13147
http://www.ncbi.nlm.nih.gov/pubmed/26400943
Schauer C, Tong T, Petitjean H, Blum T, Peron S, Mai O, Schmitz F, Boehm U, Leinders-Zufall T (2015)
Hypothalamic gonadotropin releasing hormone (GnRH) receptor neurons fire in synchrony with the female reproductive cycle.
J Neurophysiol Jun 10:jn.00357.2015. doi: 10.1152/jn.00357.2015.
http://www.ncbi.nlm.nih.gov/pubmed/26063780
Schmitz F. (2014)
Presynaptic [Ca2+] and GCAPs: aspects on the structure and function of photoreceptor ribbon synapses.
Front. Mol. Neurosci., 06 February 2014 Volume 7 - 2014
http://www.frontiersin.org/molecular_neuroscience/10.3389/fnmol.2014.00003/abstract
Silke Wahl, Rashmi Katiyar and Frank Schmitz.
A Local, Periactive Zone Endocytic Machinery at Photoreceptor Synapses in Close Vicinity to Synaptic Ribbons.
The Journal of Neuroscience,2013 June 19;33(25)10278-10300April 9, 2014.34(15):5245-5260
http://www.jneurosci.org/content/33/25/10278.full.pdf+html
Matti U, Pattu V, Halimani M, Schirra C, Krause E, Liu Y, Weins L, Fang Chang H, Guzman R, Olausson J,Freichel M, Schmitz F, Pasche M, Becherer U, Bruns D, Rettig J.
Synaptobrevin2 is the v-SNARE required for cytotoxic T-lymphocyte lytic granule fusion.
Nat Commun. 2013 Feb 5;4:1439. doi: 10.1038/ncomms2467
http://www.nature.com/ncomms/journal/v4/n2/full/ncomms2467.html
Elena Alvarez-Baron1,*, Katrin Michel1,*,Tobias Mittelstaedt1, Thoralf Opitz2,3, Frank Schmitz5,Heinz Beck2,3, Dirk Dietrich4, Albert J. Becker1, and Susanne Schoch1
RIM3γ and RIM4γ Are Key Regulators of Neuronal Arborization.
J Neurosci. 2013 Jan 9;33(2):824-39
http://www.jneurosci.org/content/33/2/824.full
Schmitz F, Natarajan S, Venkatesan JK, Wahl S, Schwarz K, Grabner CP.
EF hand-mediated Ca and cGMP signaling in photoreceptor synaptic terminals.
Front Mol Neurosci., 2012;5:26. Epub 2012 Feb 29.
http://www.ncbi.nlm.nih.gov/pubmed?term=22514320[uid]
Schwarz K*, Natarajan S*, Kassas N, Vitale N, Schmitz F
The Synaptic Ribbon Is a Site of Phosphatidic Acid Generation in Ribbon Synapses.
J. Neurosci., 2011 Nov 2; 31(44): 15996-16011. * gleichberechtigte Erstautoren.
http://www.jneurosci.org/content/31/44/15996.full
Ritter LM, Khattree N, Tam B, Moritz OL, Schmitz F, Goldberg AF.
In Situ Visualization of Protein Interactions in Sensory Neurons: Glutamic Acid-Rich Proteins (GARPs) Play Differential Roles for Photoreceptor Outer Segment Scaffolding.
J. Neurosci., 2011 Aug 3;31(31):11231-43.
http://www.jneurosci.org/content/31/31/11231.long
Venkatesan J.K.*, Natarajan S.*, Schwarz K.*, Mayer S.I., Alpadi K., Magupalli V.G. Sung C.-H., Schmitz F. (2010) NAD(H)-dependent binding of the neuronal Ca2+-sensor protein GCAP2 to photoreceptor synaptic ribbons.
J. Neurosci., 2010 May 12;30(19):6559-76.* gleichberechtigte Erstautoren.
http://www.ncbi.nlm.nih.gov/pubmed/20463219
Schmitz F. (2009) The making of synaptic ribbons: how they are built and what they do.
The Neuroscientist 15, 611-624.
http://www.ncbi.nlm.nih.gov/pubmed/19700740
Sorg H., Krueger C., Schulz T., Menger M.D., Schmitz F., Vollmar B. (2009) Effects of erythropoietin in skin wound healing are dose related.
FASEB J. 23, 3049-3058.
http://www.ncbi.nlm.nih.gov/pubmed/19403513
Schmitz, F., Fernandez-Chacon, R. (2009) Cysteine-string proteins.
The New Encyclopedia of Neuroscience3, 285-292.
Alpadi, K., Magupalli, V.G., Käppel, S., Köblitz, L., Schwarz, K., Seigel, G.M., Sung, C.H., Schmitz, F. (2008) RIBEYE recruits Munc119, the mammalian ortholog of the Caenorhabditis elegans protein unc119 to synaptic ribbons of photoreceptor synapses.
J. Biol. Chem. 283, 26461-26467.
http://www.ncbi.nlm.nih.gov/pubmed/18664567
Magupalli, V.G., Schwarz, K., Alpadi, K., Natarajan, S., Seigel, G.M., Schmitz, F. (2008) Multiple RIBEYE - RIBEYE interactions create a dynamic scaffold for the formation of synaptic ribbons.
J. Neurosci. 28, 7954-7967 (2008).
http://www.ncbi.nlm.nih.gov/pubmed/18685021
Ekici, M., Schmitz, F., Hohl, M., Seigel, G.M., Thiel, G. (2008) Chromatin structure and expression of synapsin I and synaptophysin in retinal precursor cells.
Neurochem. Int. 53, 165-172.
http://www.ncbi.nlm.nih.gov/pubmed/18692536
Wei C., Möller C.C., Altintas M.M., Li J., Schwarz K., Zacchigna S., Xie L., Heuger A., Schmid H., Rastaldi M.P., Cowan P., Kretzler M., Parilla R., Bendayan M., Gupta V., Nikolic B., Kalluri R., Carmeliet P., Mundel P., Reiser J. (2008) Modification of kidney barrier function by the urokinase receptor.
Nature Medicine 14, 55-63.
http://www.ncbi.nlm.nih.gov/pubmed/18084301
Vennekens, R., Olausson, J., Meissner, M., Bloch, W., Mathar, I., Philipp, S.E., Schmitz, F., Weissgerber, P., Nilius, B., Flockerzi, V., Freichel, M. (2007) Increased IgE-dependent mast cell activation and anaphylactic responses in mice lacking the calcium-activated nonselective cation channel TRPM4.
Nature Immunol. 3, 312-320.
http://www.ncbi.nlm.nih.gov/pubmed/17293867
Schoch, S., Mittelstaedt., T., Kaeser, P., Padgett, D., Feldman, N., Chevalevre V., Castillo, P.E., Hammer, R.E., Han,W., Schmitz, F., Lin, W., Südhof, T.C. (2006) Redundant functions of RIM1alpha and RIM2alpha in Ca2+-triggered neurotransmitter release.
EMBO J. 25, 5852-5863.
http://www.ncbi.nlm.nih.gov/pubmed/17124501
Schmitz, F., Tabares, L., Khimich, D., Strenzke, N., de la Villa-Polo, P., Castellano-Munoz, M., Bulankina, A., Moser, T., Fernandez-Chacon, R.F., Südhof, T.C. (2006) CSPalpha deficiency causes massive and rapid photoreceptor degeneration.
Proc. Natl. Acad. Sci. USA 103, 2926-2931.
http://www.ncbi.nlm.nih.gov/pubmed/16477021
Tom Dieck, S., Schmitz, F., Brandstätter, J.H. (2005) CtBPs as synaptic proteins. In: G. Chinnadurai (Ed.) CtBP family proteins, Landes Bioscience,
New York, Springer Press, pp. 105-111.
Schlüter, O., Schmitz, F., Jahn, R., Südhof, T.C. (2004) A complete genetic analysis of neuronal Rab3 function.
J. Neurosci. 24, 6629-6637.
http://www.ncbi.nlm.nih.gov/pubmed/15269275
Fernandez-Chacon, R., Wölfel, M., Nishimune, H., Tabares, L., Schmitz, F., Castellano-Munoz, M., Rosenmund, C., Montesinos, M.L., Sanes, J.R., Schneggenburger, R., Südhof, T.C. (2004) The synaptic vesicle protein CSPalpha prevents presynaptic degeneration.
Neuron 42, 237-251.
http://www.ncbi.nlm.nih.gov/pubmed/15091340
von Kriegstein, K., Schmitz, F. (2003) Expression and assembly of synaptic membrane proteins in ribbon synapses of the developing mouse retina.
Cell Tiss. Res. 311, 159-173.
http://www.ncbi.nlm.nih.gov/pubmed/12596036
Schoch, S., Castillo, P., Jo, T., Mukhargee, K., Geppert, M., Wang, Y., Schmitz, F., Malenka, R.C., Südhof, T.C. (2002) RIM1alpha forms a protein scaffold for regulating neurotransmitter release at the active zone.
Nature 415, 321-326.
http://www.ncbi.nlm.nih.gov/pubmed/11797009
Castillo P, Schoch S, Schmitz F, Südhof T.C., Malenka R.C. (2002) Rim1a is required for presynaptic long-term potentiation.
Nature 415, 327-330.
http://www.ncbi.nlm.nih.gov/pubmed/11797010
Schmitz F. (2001) Immunological heterogeneity of synaptic and extrasynaptic forms of nonerythroid alpha-spectrin in the rat retina.
Neurosci. Lett. 313, 25-28.
http://www.ncbi.nlm.nih.gov/pubmed/11684331
Schmitz F. , Augustin, I., Brose, N. (2001) Absence of the synaptic vesicle priming protein Munc13-1 from tonically active ribbon synapses of the rat retina.
Brain Res. 895, 258-263.
http://www.ncbi.nlm.nih.gov/pubmed/11259787
Schmitz F,Königstorfer A, SüdhofT.C. (2000) RIBEYE, a component of ribbon synapses: A protein?s journey through evolution provides insight into synaptic ribbon function.
Neuron 28, 857-872.
http://www.ncbi.nlm.nih.gov/pubmed/11163272
Butz S, Fernandez-Chacon R, Schmitz F, Jahn R, Südhof T.C. (1999) Synaptotagmin III is concentrated in synapses but excluded from synaptic vesicles: a synaptic synaptotagmin absent from synaptic vesicles.
J. Biol. Chem. 274, 18290-18296.
http://www.ncbi.nlm.nih.gov/pubmed/10373432
von Kriegstein K, Schmitz F, Link E, Südhof T.C. (1999) Distribution of synaptic vesicle proteins in the mammalian retina identifies obligatory and facultative components of synapses.
Europ. J. Neurosci. 11, 1335-1348.
http://www.ncbi.nlm.nih.gov/pubmed/10103129
Kraemer J, Schmitz F, Drenckhahn D (1999) Cytoplasmic dynein and dynactin as likely candidates for microtubule-dependent apical targeting of pancreatic zymogen granules.
Europ. J. Cell Biol. 78, 265-277.
http://www.ncbi.nlm.nih.gov/pubmed/10350215
Wang Y, Okamoto M, Schmitz F, Hofmann K, Südhof T.C. (1997) RIM is a putative Rab3 effector in regulating synaptic - vesicle fusion.
Nature 388, 593-598.
http://www.ncbi.nlm.nih.gov/pubmed/9252191
Schmitz F , Bechmann M , Drenckhahn D (1996) Purification of synaptic ribbons, structural components of the active zone complex of photoreceptor synapses.
J. Neurosci. 16, 7109-7116.
http://www.ncbi.nlm.nih.gov/pubmed/8929420
Dr.-Eduard-Martin-Preis
Wir gratulieren unserer ehemaligen Doktorandin, Frau Dr. med. Marie-Lisa Eich, zur Verleihung des Dr.-Eduard-Martin-Preises, den sie in Anerkennung ihrer wissenschaftlichen Leistungen von der Universitätsgesellschaft des Saarlandes verliehen bekommen hat!
Herzlichen Glückwunsch!