VLGR1/ADGRV1 (very large G protein-coupled receptor-1) is the largest known adhesion G protein-coupled receptor. Mutations in VLGR1/ADGRV1 cause Usher syndrome (USH), the most common form of hereditary deaf-blindness, and have been additionally linked to epilepsy. Although VLGR1/ADGRV1 is almost ubiquitously expressed, little is known about the subcellular function and signalling of the VLGR1 protein and thus about mechanisms underlying the development of diseases. Using affinity proteomics, we have identified key components of autophagosomes as putative interacting proteins of VLGR1. In addition, whole transcriptome sequencing of the retinae of the Vlgr1/del7TM mouse model revealed altered expression profiles of gene-related autophagy. Monitoring autophagy by immunoblotting and immunocytochemistry of the LC3 and p62 as autophagy marker proteins revealed evoked autophagy in VLGR1-deficient hTERT-RPE1 cells and USH2C patient-derived fibroblasts. Our data demonstrate the molecular and functional interaction of VLGR1 with key components of the autophagy process and point to an essential role of VLGR1 in the regulation of autophagy at internal membranes. The close association of VLGR1 with autophagy helps to explain the pathomechanisms underlying human USH and epilepsy-related to VLGR1 defects.

VLGR1/ADGRV1 (very large G protein-coupled receptor-1) is the largest adhesion G protein-coupled receptor aGPCRs. Mutations in VLGR1/ADGRV1 are associated with human Usher syndrome (USH), the most common form of deaf-blindness, and also with epilepsy in humans and in mice. Although VLGR1 is almost ubiquitously expressed in CNS and ocular and inner ear sensory cells. Little is known about the pathogenesis of the diseases related to VLGR1. We previously identified VLGR1 as a vital component of focal adhesions (FA) serving as a metabotropic mechanoreceptor that controls cell spreading and migration. FAs are highly dynamic and turnover frequently in response to internal and external signals. Here, we aimed to elucidate how VLGR1 participates in FA turnover. Nocodazole washout assays and live-cell imaging of RFP-paxillin consistently demonstrated that FA disassembly was not altered, de novo assembly of FA was significantly delayed in Vlgr1-deficient astrocytes indicating that VLGR1 is enrolled in the assembly of FAs. In FRAP experiments recovery rates were significantly reduced in Vlgr1-deficient FAs, indicating reduced turnover kinetics in VLGR1-deficient FAs. We showed that VLGR1 regulates cell migration by controlling the FA turnover during their assembly. From this, we expect novel insights into pathomechanisms related to pathogenic dysfunctions of VLGR1.