Blanco-Redondo Lab

Molecular and physiological analysis of two novel adhesion GPCRs (CG15556/ketchup and CG11318/mayo) in Drosophila melanogaster

Only few aGPCRs are well known and described in Drosophila, thus we re-screened for novel aGPCRs genes and recently discovered CG15556/ketchup and CG11318/mayo. Phylogenetical studies shown that these two new aGPCRs do not have any homolog in vertebrates, therefore they are still orphan with respect to their activation, molecular function or signal transduction.

One of the aims of the present project is to test, using cell culture techniques, whether these receptors show cell surface expression using an enzyme linked immunosorbent assay (ELISA) as a read out. In addition, one of the features of these receptors class is an autoproteolytic cleavage event that occurs at the at the GPCR autoproteolytic site (GPS) which cleaves the GPCR into an NTF (N-terminal fragment) and a CTF (C-terminal fragment). We will use cell culture -based assays to test whether the two newly identified receptors can cleave. Furthermore, based on the observation that aGPCRs display constitutively activity upon deletion of the NTF we will perform experiments to see if these two receptors have a tethered peptide agonist located within the conserved GPS site that can bind and activate the aGPCR.

Ivestigation of adhesion GPCR signaling pathways

In preparation for this project, we re-screened the Drosophila genome for the presence of genes with aGPCR hallmark domain structures, the GAIN and 7TM domain pair, and identified a gene, CG15744/Remoulade, that is an ortholog in the vertebrate adhesion GPCR subfamily III/ADGRA. This family includes the receptors ADGRA2/Gpr124 and ADGRA3/Gpr125, which partake in cell-cell and cell-matrix interactions that are involved in establishment of sealed organ boundaries such as the blood-brain or blood-testis barriers. ADGRA2 cooperates with other GPCRs of the Frizzled family, and the transmembrane proteins RECK and Lrp5/6. Collectively these proteins form a cell surface complex that acts as a recognition platform for Wnt ligands. Intriguingly this signal transduction machine requires the adhesion GPCR ADGRA2 but works independent of its 7TM domain. Knowledge of the structural dynamics of this complex is limited and pharmacological and in vivo systems that would allow its characterization are scarce.

In the proposed project we aim to molecularly and pharmacologically characterize the newly identified Drosophila melanogaster ADGRA homolog CG15744/Remoulade. For that purpose, we will use a proteomic/mass spectrometric approach to identify additional interaction partners of Remoulade. Through FRET/BRET assays we will interrogate the Remoulade signaling pathway and study conditions for receptor/co-receptor/ligand assembly and disassembly. Finally, hypotheses on the molecular mechanisms of ADGRA signaling can be readily tested under in vivo conditions by virtue of a Drosophila genomic engineering platform that can rapidly produce allelic Remoulade variants of interest. Collectively, this will allow for a better understanding of how this unusual adhesion GPCR subfamily executes its signaling functions. 

​Investigation of adhesion GPCR signaling in blood-brain barrier development and function (funded by the Faculty of Medicine, Leipzig University)​​

• Genevieve Auger​​ (PhD student)
• Fernando Vieira (PhD student)

Former members

Javier Pereira (Erasmus student)
Irene Ginés (Erasmus student)
Lena Müller (Bachelor/Master student)​

Scholz N, Dahse AK, Kemkemer M, Bormann A, Auger GM, Vieira Contreras F, Ernst LF, Staake H, Körner MB, Buhlan M, Meyer-Mölck A, Chung YK, Blanco-Redondo B, Klose F, Jarboui MA, Ljaschenko D, Bigl M, Langenhan T (2023). Molecular sensing of mechano- and ligand-dependent adhesion GPCR dissociation. Nature, 615(7954), 945-953.

Buettner JM, Sowoidnich L, Gerstner F, Blanco-Redondo B, Hallermann S, Simon CM (2022). p53-dependent c-Fos expression is a marker but not executor for motor neuron death in spinal muscular atrophy mouse models. Front Cell Neurosci, 16, 1038276.

Korobeynikov VA, Lyashchenko AK, Blanco-Redondo B, Jafar-Nejad P, Shneider NA (2022). Antisense oligonucleotide silencing of FUS expression as a therapeutic approach in amyotrophic lateral sclerosis. Nat Med, 28, 104-116.

Buettner JM, Sime Longang JK, Gerstner F, Apel KS, Blanco-Redondo B, Sowoidnich L, Janzen E, Langenhan T, Wirth B, Simon CM (2021). Central synaptopathy is the most conserved feature of motor circuit pathology across spinal muscular atrophy mouse models. iScience, 24, 103376.

Simon CM, Blanco-Redondo B, Buettner JM, Pagiazitis JG, Fletcher EV, Sime Longang JK, Mentis GZ (2021). Chronic Pharmacological Increase of Neuronal Activity Improves Sensory-Motor Dysfunction in Spinal Muscular Atrophy Mice. J Neurosci, 41, 376-389.

Blanco-Redondo B, Nuwal N, Kneitz S, Nuwal T, Halder P, Liu Y, Ehmann N, Scholz N, Mayer A, Kleber J, Kahne T, Schmitt D, Sadanandappa MK, Funk N, Albertova V, Helfrich-Forster C, Ramaswami M, Hasan G, Kittel RJ, Langenhan T, Gerber B, Buchner E (2019). Implications of the Sap47 null mutation for synapsin phosphorylation, longevity, climbing proficiency and behavioural plasticity in adult Drosophila. J Exp Biol, 222, 203505.​

Blanco-Redondo B, Langenhan T (2018). Parallel Genomic Engineering of Two Drosophila Genes Using Orthogonal attB/attP Sites. G3 (Bethesda), 8(9), 3109-3118.​

Blanco Redondo B, Bunz M, Halder P, Sadanandappa MK, Mühlbauer B, Erwin F, Hofbauer A, Rodrigues V, VijayRaghavan K, Ramaswami M, Rieger D, Wegener C, Förster C, Buchner E (2013). Identification and stuctural characterization of interneurons of the Drosophila brain by monoclonal antibodies of the würzburg hybridoma library. Plos One, 8(9):e75420.

Sadanandappa MK, Blanco Redondo B, Michels B, Rodrigues V, Gerber B, VijayRaghavan K, Buchner E, Ramaswami M (2013). Synapsin function in Gaba-ergic interneurons is required for short-term olfactory habituation. J Neurosci, 33(42):16576-85.​