And I think the main new thing that came out of our work was that these digestive systems do not exist only. in eating cells, in cells that are professionally involved, like macrophages or white blood cells, in the uptake and destruction of foreign bacteria, foreign materials in general. But that every cell type, even nerve cells and muscle cells, have a digestive system, have lysosomes.
And so this really led to the discovery that what in the original... Protosaur was essentially a function connected with feeding and digesting of food, had been converted into higher organisms, into all kinds of different functions. This basic digestive function, function of taking up, really had a...
specialized functions in different cell types. In the kidney, they would be involved in the uptake and digestion of proteins that have passed through the filter. tubules of the kidney and so on in the liver will be different in the in the thyroid lysosomes would be involved in the digestion of thyroxine, the thyroid hormone from the thyroglobulin, and so on and so on and so on. And then a more general function was also discovered, which was important even for cells like muscle cells or nerve cells that hardly are involved in taking up foreign materials. And this is a function which I didn't discover, but I call it autophagy.
I invented a few words in my life. That's probably again my classical education. And autophagy is a self-eating by cells. It's a mechanism whereby small Bits of the cell are segregated.
It's a complex mechanism. It's segregated within a membrane and then conveyed to lysosomes for breakdown. So this is autophagy.
Self-eating is one of the mechanisms whereby cells degrade their own substance and replace it. So it's part of turnover. And so autophagy is involved even in cells that do not carry out any sort of endocytosis.