Wednesday, October 21, 2020

Need THE guide for today's proteomics for medical collaborators?

 Is this the guide to today's proteomics technology that Carl Sagan would have written? Something that breaks down the crazy stuff we do that is branching into hundreds of distinct directions and makes it as approachable as possible? 

If not, it's as close of an attempt as I've ever seen and it makes me very happy.  100% recommended for sending to that person you think will be cool to work with.  

Monday, October 12, 2020

STAMPS -- Build Metabolomics Assays From the Protein Level!


I'd love to have an argument with you about what "Metabolomics" actually means. To me, the sticker is that whole "-omics" part of the word. Wait. Terrible idea time. 

I'll argue all day that "proteomics" is only just now starting to happen routinely. Here is the argument, though, I'm not sure "metabolomics" is really happening yet. We know that only a small subsection of the metabolites in a cell will stick to reverse phase chromatography, and an even smaller section of those will ionize in one polarity and an even smaller section of those will survive ionization and out of those you'll confidently identify maybe 10% , maybe 30% of them?  If you haven't tried global metabolomics, give it a whirl. Then tell me how you figure out which of the 25 things confidently labeled as "inosine" is inosine. (The second one is probably hypoxanthine, it doesn't survive electrospray very well.)  

What was I typing abou....STAMPS! You can read about it here.

STAMPS dares to ask the question: "Why are you trying to quantify these frustrating small molecules, when you could be quantifying the proteins responsible for making and degrading them?"

And you say: "Because it would take me 3 miserable months to make the targeted assays"

And they said: "Oh. Here you go. We made them all for you." (In mouse, so far, but more is clearly coming)

This thing is super sweet. Go into the database and find the metabolic pathway you're interested in. (They've got 16,000 proteins in mouse available so far) 

Put a checkmark on the proteins that you want, right in the metabolic pathway for the thing you're interested in. 

Check the spectra of your targets, if you're interested. 

And download your assay. Formatted for input into Skyline! 

Is this still sorta targeted protein quan and not proteomics? Maybe. But if you've got the ability to choose from all the things, to me, that counts. I'll be even more pumped when they set up human, but if I was really interested it wouldn't be all that hard to port this with Picky or Phosphopedia or similar. 

Sunday, October 11, 2020

PRiSM -- A thought experiment on Protein rather than Peptide Spectral Matches!

(Image credit: Lucas Vieira for making this and putting it in the open domain!

Proteomics hasn't been around all that long (not real proteomics, anyway) but we have been around long enough to develop a nice cognitive box for us to work within. 

The answers to to these questions are something like:
1) We do the peptide because it is WAY easier. 
2) You can do it. I mean....they did it.... I couldn't do it. 
3) You need some serious math and a lot of firepower. 
4) Pros? It totally works and they can find things that traditional engines can't.
5) Cons? It's hard. Like seriously hard. 3 hours per MS/MS spectrum per computational core hard, but this is a thought experiment, not a practical optimization study. 

We know there are places that our bottom-up search engines just don't work well. Maybe there is an alternative! 

Saturday, October 10, 2020

Do you have a strong Opinion on Proteomics? This special edition wants to hear it!

 I know you have some opinions about what is good and maybe what is bad in proteomics right now. (I'm anything could possibly be bad about proteomics!) If you're tired of saying that opinion over and over again to yourself, and think the whole world should hear it -- now is your chance, cause this special edition in Proteomes is accepting reviews now. 

How much do they want your review? No page charges! (Don't tell anyone at Elfseverer about this. They might literally die.)  

I'm not kidding about it being an opinion piece, special guest editor Matthew Padula described his hope of assembling a "warts and all" compilation of where we are today, so we can take it apart and figure out how to fix it all to get to the next level.

Super cool idea, right? 

Friday, October 9, 2020

Reminder you can control your EasyNLCs from your PC!

 Probably everyone already knows this? Just in case, you can totally control your EasyNLC systems from your computer. It makes remoting in a lot easier. I just confirmed today that it is compatible with the Easy1200 system.

In our test group of mass spectrometrists considered "grumpy" and "deficient in Vitamin D" by their colleagues, we found a 12% reduced incidence in road rage when they were running the horrible "flush air" script on their horrible commutes. 

You can get the installation documents from the great UWPR page here

Thursday, October 8, 2020

Fragment mass prediction for phosphosite localization!

Could we improve on current phosphorylation site localization strategies? This group sure seems to think so and this new approach seems simple enough with all this deep learning peptide stuff happening to work into a lot of new workflows! 

If I get what they're doing, they use the deep learning model for the unmodified peptides and use the phospho and phospho loss (?) shift to score the localization. The plots vs the traditional approach suggest they're onto something solid. 

Wednesday, October 7, 2020

The Carrier Proteome Effect in Single Cell Proteomics!

 I saw this one Twitter a few days ago and I couldn't find it anywhere. I think there might be a preprint, but I'm leaving it here so I don't lose it again.

Direct video link is here. 

Tuesday, October 6, 2020

Match between runs for Reporter Ion Quan?!?!?


Have you ever tried to combine multiple TMT studies? I'm paraphrasing, but Akhilesh Pandey said "two will work, and three is okay, but the amount of loss by your fourth plex makes it not worth it" and I have found that to be 100% true in my hands. Our sampling is stochaistic, which is fun to say, but I'm not sure that I'm using the word correctly. The Venn diagram of the peptides that you're able to fragment and identify in each plex that you add gets progressively less overlapping. In today's instruments that are blindingly fast, we're getting loads more fragment ions but that doesn't necessarily translate to higher percentages of actual identified ones.

Isobaric match between runs (IMBR) allows you to link data from fragmented but not identified peptides back to the identified ones from other plexes. 

I'm legit blown away. There are at least 10 different studies on hard drives sitting around here that this should help with. 

Oh, and they built a new algorithm to normalize without using a pooled channel. 'Cause, you know, this wasn't incredible enough. And these appear to now be built into MaxQuant and Perseus now! 



I was on a conference call the other day and someone said that we needed more tools for combining TMT plexes. If you're not about to start updating your MaxQuant after reading this post, you should 100% check out IRS from Phil Wilmarth. You'll need to use R to do this, but you can pretty much follow anything Phil does and copypasta what he writes directly into R and just run it.