FAM161A, a Novel Centrosomal-Ciliary Protein Implicated in Autosomal Recessive Retinitis Pigmentosa

Retinitis pigmentosa (RP) is an inherited disease of the retina leading to vision impairment due to progressive photoreceptor cell death. Homozygous and compound heterozygous null mutations in the CRX-regulated FAM161A gene of unknown function were identified as a cause for autosomal recessive RP (RP28) in patients from India, Germany, Israel, the Palestinian territories, and the USA. The FAM161A protein has been found to be localized to the connecting cilium, the basal body, and the adjacent centriole in mammalian photoreceptors and was also present in synaptic layers and ganglion cells of the retina. In addition, FAM161A was shown to be part of microtubule-organizing centers in cultured cells and associates with the intracellular microtubule network. Moreover, FAM161A directly binds to microtubules and increases the acetylation of a-tubulin. An evolutionary highly conserved, C-terminal protein domain (UPF0564) of FAM161A was shown to mediate microtubule association, homo-and heterotypic interaction among UPF0564-containing proteins and binding to several ciliopathy-associated proteins. In summary, FAM161A is a novel centrosomal-ciliary protein that likely is implicated in the regulation of microtubule-based cellular processes in the retina.