ORP2 is an intracellular cholesterol transporting protein

What is it about?

Oxysterol-binding protein (OSBP) and related proteins (ORPs) are a large protein family known to bind lipids including cholesterol and phosphoinositides and regulate multiple cellular functions such as lipid homeostasis and cell signaling. In this work we investigate the functions of oxysterol-binding protein related protein 2 (ORP2) in intracellular cholesterol transport. We also determine the binding affinity of ORP2 for certain phosphoinositides and show that it localizes to intracellular organelles called endosomes/lysosomes and interacts with the closely related cholesterol transport protein, ORP1L.

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Why is it important?

We identify ORP2 as a novel cholesterol transporting protein involved in the intracellular cholesterol transport between organelles called endosomes/lysosomes and the cell surface (plasma membrane). We also show that the lack of ORP2 protein results in cholesterol accumulation within endosomes/lysosomes. Cholesterol transport towards the plasma membrane is important e.g. for maintaining appropriate intracellular cholesterol levels, plasma membrane lipid composition, cell morphology and cell signaling, and the disturbances in cholesterol transport are known to be major causative factors in multiple diseases.