RANBP2/Nup358 (Ran Binding Protein 2) is a nucleoporin and a key component of the nuclear pore complex. Through its multiple functions (e.g. SUMOylation, regulation of nucleocytoplasmic transport) and subcellular localizations (e.g. at the nuclear envelope, kinetochores, annulate lamellae), it is involved in many cellular processes. RANBP2 dysregulation or mutation leads to the development of human pathologies, such as Acute Necrotizing Encephalopathy 1 (ANE1), cancer, neurodegenerative diseases and it is also involved in viral infections. The chromosomal region containing the RANBP2 gene is highly dynamic, with high structural variation and recombination events that led to the appearance of a gene family called RGPD (RANBP2 and GCC2 Protein Domains), with multiple gene loss/duplication events during ape evolution. Although RGPD homoplasy and maintenance during evolution suggest they might confer an advantage to their hosts, their functions are still unknown and understudied. In this review, we discuss the appearance and importance of RANBP2 in metazoans and its function-related pathologies, caused by an alteration of its expression levels (through promotor activity, post-transcriptional or post-translational modifications), its localization or genetic mutations.