Complete loss of function of the ubiquitin ligase HERC2 causes a severe neurodevelopmental phenotype

Abstract

The ubiquitin-proteasome pathway is involved in the pathogenesis of several neurogenetic diseases. We describe a Mauritanian patient harboring a homozygous deletion restricted to two contiguous genes HERC2 and OCA2 and presenting with severe developmental abnormalities. The deletion causes the complete loss of HERC2 protein function, an E3-ubiquitin ligase. HERC2 is known to target XPA and BRCA1 for degradation and a mechanism whereby it is involved in DNA repair and cell cycle regulation. We showed that loss of HERC2 function leads to the accumulation of XPA and BRCA1 in the patient's fibroblasts and generates decreased sensitivity to apoptosis and increased level of DNA repair. Our data describe for the first time the phenotypic consequences, both at the clinical and cellular levels, of a complete loss of HERC2 function in a patient. They strongly suggest that profound ubiquitin ligase -associated dysfunction is responsible for the severe phenotype in this patient, and that dysfunction of this pathway may be involved in other patients with similar neurodevelopmental diseases.

Ferritinophagy/ferroptosis: Iron‐related newcomers in human diseases

“…Thus, ferroptosis might be an important driving mechanism to the progression of neurodegenerative diseases. Surprisingly, the complete loss of HERC2 is responsible for severe neurodevelopmental abnormalities, contributing to the pathogenesis of neurogenetic diseases (Morice‐Picard et al, ). HERC2 is a key modulator in ferritinophagy, particularly with high levels of cellular iron (Mancias et al, ).…”

“…Alzheimer's disease (AD), share several common processes in neural cell death, including iron accumulation and excess oxidative stress ( abnormalities, contributing to the pathogenesis of neurogenetic diseases (Morice-Picard et al, 2016). HERC2 is a key modulator in ferritinophagy, particularly with high levels of cellular iron (Mancias et al, 2015).…”

Peptidomic analysis of blastocyst culture medium and the effect of peptide derived from blastocyst culture medium on blastocyst formation and viability

“…In addition to the HERC2 gene, the HERC2 protein has been increasingly studied in recent years. The HERC2 protein, an E3 ubiquitin ligase belonging to the HERC protein family, has been shown to participate in multiple biological processes, including iron metabolism (Moroishi, Yamauchi, Nishiyama, & Nakayama, ), cell proliferation (Cubillos‐Rojas et al, ), cell cycle regulation (Mao, Sethi, Zhang, & Wang, ), DNA repair (Bekker‐Jensen et al, ), and apoptosis sensitivity (Morice‐Picard et al, ). Iron is essential for embryo growth‐related functions, including DNA synthesis, mitochondrial function, and immune response.…”

HERCing: Structural and Functional Relevance of the Large HERC Ubiquitin Ligases

“…In humans, the HERC2 gene locates to chromosome 15 among genes responsible for such disorders as Angelman and Prader-Willi syndromes and Autism spectrum disorders (Ji et al, 1999; Dimitropoulos and Schultz, 2007; Roberts et al, 2014). Recessive mutations in the HERC2 locus are related to symptoms ranging from cognitive delay, ataxia, speech disorders, microcephalia, seizures, facial dysmorphism, hypopigmentation, and other secondary signs such as infections and behavioural alterations (Puffenberger et al, 2012; Harlalka et al, 2013; Neubert et al, 2013; Han et al, 2016; Morice-Picard et al, 2016).…”