Organelle biogenesis and motility

Organelle biogenesis and motility

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Head of Unit

Maria Vittoria Schiaffino

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Mammalian cells contain a specific repertoire of membrane-bound organelles that are essential for their survival and role within the organism. The biogenesis, motility, signaling and intracellular connections of these organelles is required for their proper function and, when altered, can result in a variety of human diseases.

Research activity

The group investigates the mechanisms underlying these processes by focusing on the molecular pathogenesis of ocular albinism type 1, a genetic disorder characterized by visual impairment and by abnormalities of melanosomes, a special type of lysosome-related organelles, devoted to the synthesis and transport of melanin in pigment cells. In fact, loss-of-function of the ocular albinism gene OA1, encoding a unique G protein-coupled receptor localized to melanosomes, results in aberrant size, number and distribution of the organelles. Recent findings of this Unit indicate that the proper biogenesis of melanosomes requires both tight juxtaposition with mitochondria, through fibrillar bridges resembling the protein tethers linking mitochondria and endoplasmic reticulum, and dedicated transcriptional programs, regulated by the microphthalmia family of transcription factors.

A second line of research in the lab is focused on the cellular adaptations to nutrient restriction, including long-term epigenetic and transcriptional modifications. To this aim, the group is investigating the sensing and signaling pathways induced by amino acid deprivation and leading to epigenetic/transcriptional effects, by taking advantage of our previous observation that prolonged deprivation of essential amino acids causes selective and reversible reactivation of stably integrated and silenced transcriptional units of the genome, such as exogenous transgenes and HIV provirus.