Estimate the protein content of over 1,000 human cell types!

 

This came up when some old friends were visiting my lab this week. 

Where do I get these estimates for how much protein concentration should be in each single human cell? 

A couple of places, but the best organized place to start is the amazing 

Human Cell Tree Map - https://humancelltreemap.mis.mpg.de/

Is is the topic of this recent PNAS paper. 

Now - they did this the hard way. They took tissue from people counted the cells and weighed them. For real. It was an amazing amount of work. Supplemental File 3 is an amazing resource for getting these numbers. They didn't just come frome one white guy either. Cells were counted and measured from MANY donors.

Now - according to Harvard BioNumbers  - about 20-30% of each human cell is protein. 

Quick test of the data. In the screenshot above I have went to Male/Digestive System/Liver/Hepatocytes. And it gives me a range from 3.17 e9 to 1.49 e8 for the cells.

If it is a Sunday morning and my brain hasn't fired up quite yet. I go to Google convert and I have it convert 

So the low range for a hepatocyte is 3,170 pg and 20% of that is something like 640 pg of protein. 30% is something like 900pg of protein. Since I've got hepatocytes from patients under multiple conditions coming in this Friday, I'm pretty up to date on this. 

And this paper from a few years ago compared different human liver cell lines/types using deep proteomics and the Proteomics Ruler. 

And they calculated something like 700pg for a male human hepatocyte, so we're in the right range-ish.

There are clearly HUGE error bars here, right? But at least it points you in the right direction if someone comes in and says "can you do this cell?" And you can do a quick look and say...."an eosinophil doesn't sound like any fun at all!"