Primary cilia are cellular surface projections enriched in receptors and signaling molecules, acting as signaling hubs that respond to stimuli. Malfunctions in primary cilia have been linked to human diseases, including retinopathies and ocular defects. Here, we focus on TMEM107, a protein localized to the transition zone of primary cilia. TMEM107 mutations were found in patients with Joubert and Meckel-Gruber syndromes. A mouse model lacking Tmem107 exhibited eye defects such as anophthalmia and microphthalmia, affecting retina differentiation. Tmem107 expression during prenatal mouse development correlated with phenotype occurrence, with enhanced expression in differentiating retina and optic stalk. TMEM107 deficiency in retinal organoids resulted in the loss of primary cilia, down-regulation of retina-specific genes, and cyst formation. Knocking out TMEM107 in human ARPE-19 cells prevented primary cilia formation and impaired response to Smoothened agonist treatment because of ectopic activation of the SHH pathway. Our data suggest TMEM107 plays a crucial role in early vertebrate eye development and ciliogenesis in the differentiating retina.

• MeSH
• Humans MeSH
• Membrane Proteins genetics   metabolism   MeSH
• Mice MeSH
• Polycystic Kidney Diseases * genetics   MeSH
• Ciliary Motility Disorders * genetics   metabolism   MeSH
• Retina metabolism   MeSH
• Retinitis Pigmentosa * metabolism   MeSH
• Pregnancy MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Pregnancy MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Membrane Proteins MeSH
• TMEM107 protein, human MeSH Browser
• Tmem107 protein, mouse MeSH Browser

Alterations in the balance between skeletogenesis and adipogenesis is a pathogenic feature in multiple skeletal disorders. Clinically, enhanced bone marrow adiposity in bones impairs mobility and increases fracture risk, reducing the quality of life of patients. The molecular mechanism that underlies the balance between skeletogenesis and adipogenesis is not completely understood but alterations in skeletal progenitor cells' differentiation pathway plays a key role. We recently demonstrated that parathyroid hormone (PTH)/PTH-related peptide (PTHrP) control the levels of DEPTOR, an inhibitor of the mechanistic target of rapamycin (mTOR), and that DEPTOR levels are altered in different skeletal diseases. Here, we show that mutations in the PTH receptor-1 (PTH1R) alter the differentiation of skeletal progenitors in two different skeletal genetic disorders and lead to accumulation of fat or cartilage in bones. Mechanistically, DEPTOR controls the subcellular localization of TAZ (transcriptional co-activator with a PDZ-binding domain), a transcriptional regulator that governs skeletal stem cells differentiation into either bone and fat. We show that DEPTOR regulation of TAZ localization is achieved through the control of Dishevelled2 (DVL2) phosphorylation. Depending on nutrient availability, DEPTOR directly interacts with PTH1R to regulate PTH/PTHrP signaling or it forms a complex with TAZ, to prevent its translocation to the nucleus and therefore inhibit its transcriptional activity. Our data point DEPTOR as a key molecule in skeletal progenitor differentiation; its dysregulation under pathologic conditions results in aberrant bone/fat balance.

• Keywords
• DEPTOR, PTH signaling, TAZ, Wnt, osteogenesis, skeletal differentiation,
• Publication type
• Journal Article MeSH

RNF43 is an E3 ubiquitin ligase and known negative regulator of WNT/β-catenin signaling. We demonstrate that RNF43 is also a regulator of noncanonical WNT5A-induced signaling in human cells. Analysis of the RNF43 interactome using BioID and immunoprecipitation showed that RNF43 can interact with the core receptor complex components dedicated to the noncanonical Wnt pathway such as ROR1, ROR2, VANGL1, and VANGL2. RNF43 triggers VANGL2 ubiquitination and proteasomal degradation and clathrin-dependent internalization of ROR1 receptor and inhibits ROR2 activation. These activities of RNF43 are physiologically relevant and block pro-metastatic WNT5A signaling in melanoma. RNF43 inhibits responses to WNT5A, which results in the suppression of invasive properties of melanoma cells. Furthermore, RNF43 prevented WNT5A-assisted development of resistance to BRAF V600E and MEK inhibitors. Next, RNF43 acted as melanoma suppressor and improved response to targeted therapies in vivo. In line with these findings, RNF43 expression decreases during melanoma progression and RNF43-low patients have a worse prognosis. We conclude that RNF43 is a newly discovered negative regulator of WNT5A-mediated biological responses that desensitizes cells to WNT5A.

• Keywords
• BRAF V600E, RNF43, ROR1, VANGL1, WNT5A, cancer biology, cell biology, human, melanoma, mouse,
• MeSH
• Neoplasm Invasiveness genetics   MeSH
• Melanoma * genetics   pathology   prevention & control   MeSH
• Mice, Inbred NOD MeSH
• Mice MeSH
• Wnt-5a Protein genetics   metabolism   MeSH
• Signal Transduction * MeSH
• Ubiquitin-Protein Ligases genetics   metabolism   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Wnt-5a Protein MeSH
• RNF43 protein, human MeSH Browser
• Ubiquitin-Protein Ligases MeSH
• WNT5A protein, human MeSH Browser

Mutations in genes affecting primary cilia cause ciliopathies, a diverse group of disorders often affecting skeletal development. This includes Jeune syndrome or asphyxiating thoracic dystrophy (ATD), an autosomal recessive skeletal disorder. Unraveling the responsible molecular pathology helps illuminate mechanisms responsible for functional primary cilia. We identified two families with ATD caused by loss-of-function mutations in the gene encoding adrenergic receptor kinase 1 (ADRBK1 or GRK2). GRK2 cells from an affected individual homozygous for the p.R158* mutation resulted in loss of GRK2, and disrupted chondrocyte growth and differentiation in the cartilage growth plate. GRK2 null cells displayed normal cilia morphology, yet loss of GRK2 compromised cilia-based signaling of Hedgehog (Hh) pathway. Canonical Wnt signaling was also impaired, manifested as a failure to respond to Wnt ligand due to impaired phosphorylation of the Wnt co-receptor LRP6. We have identified GRK2 as an essential regulator of skeletogenesis and demonstrate how both Hh and Wnt signaling mechanistically contribute to skeletal ciliopathies.

• Keywords
• GRK2, Wnt, asphyxiating thoracic dystrophy, hedgehog, smoothened,
• MeSH
• Ellis-Van Creveld Syndrome * MeSH
• G-Protein-Coupled Receptor Kinase 2 genetics   MeSH
• Humans MeSH
• Mutation MeSH
• Hedgehog Proteins * genetics   MeSH
• Wnt Signaling Pathway MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• GRK2 protein, human MeSH Browser
• G-Protein-Coupled Receptor Kinase 2 MeSH
• Hedgehog Proteins * MeSH

Oct4-mediated reprogramming has recently become a novel tool for the generation of various cell types from differentiated somatic cells. Although molecular mechanisms underlying this process are unknown, it is well documented that cells over-expressing Oct4 undergo transition from differentiated state into plastic state. This transition is associated with the acquisition of stem cells properties leading to epigenetically "open" state that is permissive to cell fate switch upon external stimuli. In order to contribute to our understanding of molecular mechanisms driving this process, we characterised human fibroblasts over-expressing Oct4 and performed comprehensive small-RNAseq analysis. Our analyses revealed new interesting aspects of Oct4-mediated cell plasticity induction. Cells over-expressing Oct4 lose their cell identity demonstrated by down-regulation of fibroblast-specific genes and up-regulation of epithelial genes. Interestingly, this process is associated with microRNA expression profile that is similar to microRNA profiles typically found in pluripotent stem cells. We also provide extensive network of microRNA families and clusters allowing us to precisely determine the miRNAome associated with the acquisition of Oct4-induced transient plastic state. Our data expands current knowledge of microRNA and their implications in cell fate alterations and contributing to understanding molecular mechanisms underlying it.

• MeSH
• Cell Line MeSH
• Embryo, Mammalian * MeSH
• Fibroblasts cytology   metabolism   MeSH
• Humans MeSH
• MicroRNAs * biosynthesis   genetics   MeSH
• Octamer Transcription Factor-3 * biosynthesis   genetics   MeSH
• Gene Expression Regulation * MeSH
• Cellular Reprogramming Techniques * MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• MicroRNAs * MeSH
• Octamer Transcription Factor-3 * MeSH
• POU5F1 protein, human MeSH Browser

Vertebrate primary cilium is a Hedgehog signaling center but the extent of its involvement in other signaling systems is less well understood. This report delineates a mechanism by which fibroblast growth factor (FGF) controls primary cilia. Employing proteomic approaches to characterize proteins associated with the FGF-receptor, FGFR3, we identified the serine/threonine kinase intestinal cell kinase (ICK) as an FGFR interactor. ICK is involved in ciliogenesis and participates in control of ciliary length. FGF signaling partially abolished ICK's kinase activity, through FGFR-mediated ICK phosphorylation at conserved residue Tyr15, which interfered with optimal ATP binding. Activation of the FGF signaling pathway affected both primary cilia length and function in a manner consistent with cilia effects caused by inhibition of ICK activity. Moreover, knockdown and knockout of ICK rescued the FGF-mediated effect on cilia. We provide conclusive evidence that FGF signaling controls cilia via interaction with ICK.

• Keywords
• FGFR, ICK, cilia length, fibroblast growth factor, intestinal cell kinase,
• MeSH
• NIH 3T3 Cells MeSH
• Cilia metabolism   MeSH
• CRISPR-Cas Systems MeSH
• Fibroblast Growth Factors metabolism   MeSH
• Phosphorylation MeSH
• HEK293 Cells MeSH
• Protein Interaction Domains and Motifs MeSH
• Humans MeSH
• Models, Animal MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Protein Serine-Threonine Kinases genetics   metabolism   MeSH
• Hedgehog Proteins metabolism   MeSH
• Proteomics MeSH
• Receptor, Fibroblast Growth Factor, Type 1 metabolism   MeSH
• Receptor, Fibroblast Growth Factor, Type 3 genetics   metabolism   MeSH
• Receptor, Fibroblast Growth Factor, Type 4 metabolism   MeSH
• Receptors, Fibroblast Growth Factor genetics   metabolism   MeSH
• Signal Transduction MeSH
• Molecular Docking Simulation MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• CILK1 protein, human MeSH Browser
• Cilk1 protein, mouse MeSH Browser
• FGFR1 protein, human MeSH Browser
• FGFR3 protein, human MeSH Browser
• FGFR4 protein, human MeSH Browser
• Fibroblast Growth Factors MeSH
• Protein Serine-Threonine Kinases MeSH
• Hedgehog Proteins MeSH
• Receptor, Fibroblast Growth Factor, Type 1 MeSH
• Receptor, Fibroblast Growth Factor, Type 3 MeSH
• Receptor, Fibroblast Growth Factor, Type 4 MeSH
• Receptors, Fibroblast Growth Factor MeSH