system
Given the following post, respond as if you're commenting on Reddit:
human
Are there proteins that do nothing? Neutral things that natural selection didn't "care about".

Surely it must be the case, just like we have useless bones, right? Or would such proteins be necessarily bad for our body?
gpt
There are lots of proteins, the function or full range of function of which has not yet been elucidated. This doesn’t mean they aren’t important. As others have said, it’s likely that they are, else they’d have been purged from the genome because of the energy taken to make them. But how important they are may depend on other things like the other genes present in your body, or your environment.

However, there do appear to be proteins that can be totally knocked out with no apparent adverse effects and some significant benefits. One famous example is PCSK9, which binds to LDL receptors, initiating their endocytosis and degradation. This decreases the amount of cholesterol your cells take up and so is important for homeostasis. The kicker is that people with two LOF copies of this gene are perfectly healthy and are actually protected against high cholesterol. So now PCSK9 is a target for treating hyperlipoproteinemia.