RESUMEN
FAM20C (family with sequence similarity 20, member C) is a serine/threonine-specific protein kinase that is ubiquitously expressed and mainly associated with biomineralization and phosphatemia regulation. It is mostly known due to pathogenic variants causing its deficiency, which results in Raine syndrome (RNS), a sclerosing bone dysplasia with hypophosphatemia. The phenotype is recognized by the skeletal features, which are related to hypophosphorylation of different FAM20C bone-target proteins. However, FAM20C has many targets, including brain proteins and the cerebrospinal fluid phosphoproteome. Individuals with RNS can have developmental delay, intellectual disability, seizures, and structural brain defects, but little is known about FAM20C brain-target-protein dysregulation or about a potential pathogenesis associated with neurologic features. In order to identify the potential FAM20C actions on the brain, an in silico analysis was conducted. Structural and functional defects reported in RNS were described; FAM20C targets and interactors were identified, including their brain expression. Gene ontology of molecular processes, function, and components was completed for these targets, as well as for potential involved signaling pathways and diseases. The BioGRID and Human Protein Atlas databases, the Gorilla tool, and the PANTHER and DisGeNET databases were used. Results show that genes with high expression in the brain are involved in cholesterol and lipoprotein processes, plus axo-dendritic transport and the neuron part. These results could highlight some proteins involved in the neurologic pathogenesis of RNS.
Asunto(s)
Microcefalia , Proteínas Quinasas , Humanos , Proteínas Quinasas/metabolismo , Microcefalia/genética , Encéfalo/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas de la Matriz Extracelular/genética , Proteínas de la Matriz Extracelular/metabolismo , Quinasa de la Caseína I/genética , Quinasa de la Caseína I/metabolismoRESUMEN
FAM20C is a gene coding for a protein kinase that targets S-X-E/pS motifs on different phosphoproteins belonging to diverse tissues. Pathogenic variants of FAM20C are responsible for Raine syndrome (RS), initially described as a lethal and congenital osteosclerotic dysplasia characterized by generalized atherosclerosis with periosteal bone formation, characteristic facial dysmorphisms and intracerebral calcifications. The aim of this review is to give an overview of targets and variants of FAM20C as well as RS aspects. We performed a wide phenotypic review focusing on clinical aspects and differences between all lethal (LRS) and non-lethal (NLRS) reported cases, besides the FAM20C pathogenic variant description for each. As new targets of FAM20C kinase have been identified, we reviewed FAM20C targets and their functions in bone and other tissues, with emphasis on novel targets not previously considered. We found the classic lethal and milder non-lethal phenotypes. The milder phenotype is defined by a large spectrum ranging from osteonecrosis to osteosclerosis with additional congenital defects or intellectual disability in some cases. We discuss our current understanding of FAM20C deficiency, its mechanism in RS through classic FAM20C targets in bone tissue and its potential biological relevance through novel targets in non-bone tissues.
Asunto(s)
Anomalías Múltiples , Quinasa de la Caseína I , Fisura del Paladar , Exoftalmia , Proteínas de la Matriz Extracelular , Variación Genética , Microcefalia , Osteosclerosis , Fenotipo , Anomalías Múltiples/genética , Anomalías Múltiples/metabolismo , Anomalías Múltiples/mortalidad , Anomalías Múltiples/patología , Quinasa de la Caseína I/genética , Quinasa de la Caseína I/metabolismo , Fisura del Paladar/genética , Fisura del Paladar/metabolismo , Fisura del Paladar/mortalidad , Fisura del Paladar/patología , Exoftalmia/genética , Exoftalmia/metabolismo , Exoftalmia/mortalidad , Exoftalmia/patología , Proteínas de la Matriz Extracelular/genética , Proteínas de la Matriz Extracelular/metabolismo , Humanos , Microcefalia/genética , Microcefalia/metabolismo , Microcefalia/mortalidad , Microcefalia/patología , Osteosclerosis/genética , Osteosclerosis/metabolismo , Osteosclerosis/mortalidad , Osteosclerosis/patologíaRESUMEN
Raine syndrome is a rare, often lethal autosomal recessive condition marked by congenital malformations that range in severity. Considering that several case reports of this syndrome describe cases of stillbirth or perinatal death, information about the clinical presentation and development of this condition in mild, non-lethal cases is lacking. With that in mind, in this case report, we describe the clinical, oro-dental, and skeletal findings of a 14-year-old Brazilian patient diagnosed with a mild form of non-lethal Raine syndrome. This patient has very mild facial dysmorphia, not displaying hypoplastic nose, micrognathia, low set ears or depressed nasal bridge, which is uncommon even in other mild, non-lethal cases of RS. Furthermore, this patient has bilateral brain calcifications and a series of oro-dental abnormalities, such as amelogenesis imperfecta and recurrent periodontal abcesses. Sanger sequencing of genomic DNA identified a homozygous missense variant c.1487C > T at exon 9 of FAM20C (NM_020223.4) in the patient. The patient's mother carries the same variant but is heterozygous. This variant predicts a proline to leucine substitution in position 496 (p.P496L, NP_064608.2) previously reported, which allows for the phenotypic comparison between these cases. This way, this case report calls attention to how differently RS can appear, highlighting the importance of new non-lethal Raine syndrome case reports to help further determine the phenotypic spectrum of this condition.
Asunto(s)
Anomalías Múltiples/genética , Fisura del Paladar/genética , Exoftalmia/genética , Microcefalia/genética , Osteosclerosis/genética , Fenotipo , Anomalías Múltiples/patología , Adolescente , Quinasa de la Caseína I/genética , Quinasa de la Caseína I/metabolismo , Fisura del Paladar/patología , Dentición , Exoftalmia/patología , Proteínas de la Matriz Extracelular/genética , Proteínas de la Matriz Extracelular/metabolismo , Humanos , Masculino , Microcefalia/patología , Mutación Missense , Osteosclerosis/patologíaRESUMEN
Two siblings from a Mexican family who carried lethal Raine syndrome are presented. A newborn term male (case 1) and his 21 gestational week brother (case 2), with a similar osteosclerotic pattern: generalized osteosclerosis, which is more evident in facial bones and cranial base. Prenatal findings at 21 weeks and histopathological features for case 2 are described. A novel combination of biallelic FAM20C pathogenic variants were detected, a maternal cytosine duplication at position 456 and a paternal deletion of a cytosine in position 474 in exon 1, which change the reading frame with a premature termination at codon 207 and 185 respectively. These changes are in concordance with a negative detection of the protein in liver and kidney as shown in case 2. Necropsy showed absence of pancreatic Langerhans Islets, which are reported here for the first time. Corpus callosum absence is added to the few reported cases of brain defects in Raine syndrome. This report shows two new FAM20C variants not described previously, and negative protein detection in the liver and the kidney. We highlight that lethal Raine syndrome is well defined as early as 21 weeks, including mineralization defects and craniofacial features. Pancreas and brain defects found here in FAM20C deficiency extend the functional spectrum of this protein to previously unknown organs.
Asunto(s)
Anomalías Múltiples/genética , Quinasa de la Caseína I/genética , Fisura del Paladar/genética , Exoftalmia/genética , Proteínas de la Matriz Extracelular/genética , Microcefalia/genética , Osteosclerosis/genética , Anomalías Múltiples/metabolismo , Enfermedades del Desarrollo Óseo , Quinasa de la Caseína I/metabolismo , Fisura del Paladar/metabolismo , Cisteína/genética , Exoftalmia/metabolismo , Proteínas de la Matriz Extracelular/metabolismo , Familia , Femenino , Humanos , Recién Nacido , Islotes Pancreáticos/patología , Riñón/patología , Hígado/patología , Masculino , Microcefalia/metabolismo , Mutación , Osteosclerosis/metabolismo , Linaje , Fenotipo , Polimorfismo Genético/genéticaRESUMEN
BACKGROUND: Raine syndrome (RS) is a rare autosomal recessive bone dysplasia typified by osteosclerosis and dysmorphic facies due to FAM20C mutations. Initially reported as lethal in infancy, survival is possible into adulthood. We describe the molecular analysis and clinical phenotypes of five individuals from two consanguineous Brazilian families with attenuated Raine Syndrome with previously unreported features. METHODS: The medical and dental clinical records were reviewed. Extracted deciduous and permanent teeth as well as oral soft tissues were analysed. Whole exome sequencing was undertaken and FAM20C cDNA sequenced in family 1. RESULTS: Family 1 included 3 siblings with hypoplastic Amelogenesis Imperfecta (AI) (inherited abnormal dental enamel formation). Mild facial dysmorphism was noted in the absence of other obvious skeletal or growth abnormalities. A mild hypophosphataemia and soft tissue ectopic mineralization were present. A homozygous FAM20C donor splice site mutation (c.784 + 5 g > c) was identified which led to abnormal cDNA sequence. Family 2 included 2 siblings with hypoplastic AI and tooth dentine abnormalities as part of a more obvious syndrome with facial dysmorphism. There was hypophosphataemia, soft tissue ectopic mineralization, but no osteosclerosis. A homozygous missense mutation in FAM20C (c.1487C > T; p.P496L) was identified. CONCLUSIONS: The clinical phenotype of non-lethal Raine Syndrome is more variable, including between affected siblings, than previously described and an adverse impact on bone growth and health may not be a prominent feature. By contrast, a profound failure of dental enamel formation leading to a distinctive hypoplastic AI in all teeth should alert clinicians to the possibility of FAM20C mutations.
Asunto(s)
Anomalías Múltiples/genética , Quinasa de la Caseína I/genética , Fisura del Paladar/genética , Exoftalmia/genética , Proteínas de la Matriz Extracelular/genética , Microcefalia/genética , Anomalías de la Boca/complicaciones , Mutación , Osteosclerosis/genética , Linaje , Fenotipo , Anomalías Dentarias/complicaciones , Adolescente , Secuencia de Bases , Niño , Preescolar , Fisura del Paladar/complicaciones , Exoftalmia/complicaciones , Femenino , Humanos , Masculino , Microcefalia/complicaciones , Osteosclerosis/complicaciones , Adulto JovenRESUMEN
Protein kinase CK1 is a ser/thr protein kinase family which has been identified in the cytosol cell fraction, associated with membranes as well as in the nucleus. Several isoforms of this gene family have been described in various organisms: CK1alpha, CK1beta, CK1delta, CK1epsilon and CK1gamma. Over the last decade, several members of this family have been involved in development processes related to wnt and sonic hedgehog signalling pathways. However, there is no detailed temporal information on the CK1 family in embryonic stages, even though orthologous genes have been described in several different vertebrate species. In this study, we describe for the first time the cloning and detailed expression pattern of five CK1 zebrafish genes. Sequence analysis revealed that zebrafish CK1 proteins are highly homologous to other vertebrate orthologues. Zebrafish CK1 genes are expressed throughout development in common and different territories. All the genes studied in development show maternal and zygotic expression with the exception of CK1epsilon. This last gene presents only a zygotic component of expression. In early stages of development CK1 genes are ubiquitously expressed with the exception of CK1epsilon. In later stages the five CK1 genes are expressed in the brain but not in the same way. This observation probably implicates the CK1 family genes in different and also in redundant functions. This is the first time that a detailed comparison of the expression of CK1 family genes is directly assessed in a vertebrate system throughout development.
Asunto(s)
Quinasa de la Caseína I/genética , Regulación del Desarrollo de la Expresión Génica , Pez Cebra/embriología , Secuencia de Aminoácidos , Animales , Tipificación del Cuerpo , Quinasa de la Caseína I/metabolismo , Clonación Molecular , Cartilla de ADN , Perfilación de la Expresión Génica , Hibridación in Situ , Datos de Secuencia Molecular , Filogenia , ARN Mensajero , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Pez Cebra/genéticaRESUMEN
Protein kinase CK1 is a ser/thr protein kinase family which has been identified in the cytosol cell fraction, associated with membranes as well as in the nucleus. Several isoforms of this gene family have been described in various organisms: CK1 , CK1á, CK1δ, CK1å and CK1γ. Over the last decade, several members of this family have been involved in development processes related to wnt and sonic hedgehog signalling pathways. However, there is no detailed temporal information on the CK1 family in embryonic stages, even though orthologous genes have been described in several different vertebrate species. In this study, we describe for the first time the cloning and detailed expression pattern of five CK1 zebrafish genes. Sequence analysis revealed that zebrafish CK1 proteins are highly homologous to other vertebrate orthologues. Zebrafish CK1 genes are expressed throughout development in common and different territories. All the genes studied in development show maternal and zygotic expression with the exception of CK1å. This last gene presents only a zygotic component of expression. In early stages of development CK1 genes are ubiquitously expressed with the exception of CK1å. In later stages the five CK1 genes are expressed in the brain but not in the same way. This observation probably implicates the CK1 family genes in different and also in redundant functions. This is the first time that a detailed comparison of the expression of CK1 family genes is directly assessed in a vertebrate system throughout development.
Asunto(s)
Animales , Quinasa de la Caseína I/genética , Regulación del Desarrollo de la Expresión Génica , Pez Cebra/embriología , Secuencia de Aminoácidos , Tipificación del Cuerpo , Clonación Molecular , Quinasa de la Caseína I/metabolismo , Cartilla de ADN , Perfilación de la Expresión Génica , Hibridación in Situ , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , ARN Mensajero , Alineación de Secuencia , Pez Cebra/genéticaRESUMEN
Protein kinase CK1 denotes a family of pleiotropic serine/threonine protein kinases implicated in a variety of cellular functions. Typically, CK1 acts as a 'phosphate-directed' kinase whose targeting is primed by a single phosphorylated side chain at position n-3 or n-4 relative to serine/threonine, but increasing evidence is accumulating that CK1 can also engage some of its substrates at sites that do not conform to this canonical consensus. In the present paper, we show that CK1a phosphorylates with the same efficiency phosphopeptides primed by a phosphoserine residue at either n-3 [pS(-3)] or n-4 [pS(-4)] positions. The phosphorylation efficiency of the pS(-4) peptide, and to a lesser extent that of the pS(-3) peptide, is impaired by the triple mutation of the lysine residues in the K229KQK232 stretch to alanine residues, promoting 40-fold and 6-fold increases of Km respectively. In both cases, the individual mutation of Lys232 is as detrimental as the triple mutation. A kinetic alanine-scan analysis with a series of substituted peptide substrates in which the priming phosphoserine residue was effectively replaced by a cluster of four aspartate residues was also consistent with a crucial role of Lys232 in the recognition of the acidic determinant at position n-4. In sharp contrast, the phosphorylation of b-catenin and of a peptide including the non-canonical b-catenin site (Ser45) lacking acidic/phosphorylated determinants upstream is not significantly affected by mutations in the KKQK stretch. These data provide a molecular insight into the structural features that underlie the site specificity of CK1a and disclose the possibility of developing strategies for the preferential targeting of subsets of CK1 substrates.