Peptide quan beats RNA quan?!?!?!

This is old news, I guess.  At least everyone at the bar last night knew about this except for me.  In my defense, this field publishes a ton of stuff.  As most y'all know, my background is biology, microbiology to be precise. While I never ever did RT-PCR, I am (was?) under the impression that nothing would give you verifiable insight into the amount of a gene product in a cell the way that technique does.

What if it isn't as precise as peptide quan.  What if it wasn't even close?

Well, it seems like an accepted fact now that it is the case.  For a breakdown, take a look at this paper in Nature Reviews Genetics.

Highlights?
Protein abundances are more conserved among species than RNA abundances.  There is plenty of evidence that living systems have protein abundance levels that they are happy with and a whole lot of that regulation is at the post-translational level.

mRNA transcript abundances only partially correlate with protein abundances.  Right.  I guess it seems obvious, I think of the protein levels in a cell as this dynamic mixture, but I assumed that we could tell how much protein is present -- in a very linear way -- from the amount of RNA present...and all the evidence says that we can't.  Post translational regulation is very very important to the amount of protein that is going to be present.  Again, probably obvious, but I'll have to change my mental framework around a little.