Missing links<\/p>\n
What\u2019s most firmly established today is the final step. \u201cIf you have less translation and less protein production, that leads to the lifespan extension,\u201d Obata says. This lifespan extension, he argues, relies on improved proteostasis, the cell\u2019s ability to keep its proteins in good working order.<\/p>\n
The link between Lsp2 and ribosomes is less understood. \u201cWhat we have to find out is why this Lsp2 is preferably going to the ribosome,\u201d Obata says. \u201cThis part is still kind of a mystery.\u201d The team also couldn\u2019t directly demonstrate that fewer ribosomes cause the longer lifespan by restoring ribosome levels. \u201cRibosomal proteins are a mixture of roughly 100 different proteins,\u201d Obata told Ars. \u201cIf you want to manipulate ribosomal levels, you have to either up or down these 100 proteins at once, which is not technically possible at this moment.\u201d<\/p>\n
But even with all the details figured out, feeding longevity diets to toddlers is unlikely to become a thing in the foreseeable future, mainly because mammals, including humans, have no direct equivalent of Lsp2.<\/p>\n
Translation issues<\/p>\n
Obata thinks the best functional counterparts of Lsp2 in humans are albumin and globulins, which together make up around 90 percent of the protein in our blood. Like Lsp2, albumin is made in large amounts, turns over quickly, and is sensitive to how much protein we eat.<\/p>\n
Testing whether these proteins carry a nutritional memory just like Lsp2 does would be a stepwise process. \u201cWe have to do this first in mice, because there we can manipulate proteins directly, and then maybe in primates,\u201d Obata says. \u201cIn humans, we would have to perform studies looking at whether there is a correlation between the level of albumin and lifespan.\u201d If albumin gets confirmed as a human nutritional memory carrier, the team will still have plenty of other details to figure out.<\/p>\n
Human albumin is not particularly rich in tyrosine or phenylalanine, so if a similar mechanism exists in people, it may rely on different amino acids. \u201cWe have to find out which amino acids are key, which molecular carrier would be equivalent to Lsp2, and then whether there really is a connection between lifespan and the diet in people,\u201d Obata says.<\/p>\n