※ User Guide:

This website is free and open to all users and there is no login requirement.

Tutorial:





Frequently Asked Questions:

1. Q: How to use GPSD webserver?

A: First, you could find the prediction website in "WEB SERVER" page of GPSD. Second, enter protein sequence(s) in fasta format, which starts with a '>' followed with protein/peptide name. Then, select the phosphatase node(s). The predictor contains 9 S/T families and 3 Y families for phosphatases. Just click the "Submit" button, wait a moment, you can get the prediction results of phosphatase-specific dephosphorylation sites on substrate.

 

2. Q: How to read the GPSD results?

A: Here we use the human protein TP53 as the example. After clicking "Submit", the prediction results of PPP2CA-catalyzed sites with high threshold are shown as follows:


<1>. The table of the GPSD results

ID: The name/id of the protein sequence that you input to predict.

Position: The position of the site which is predicted to be dephosphorylated.

Code: The residue which is predicted to be dephosphorylated.

Phosphatase: The regulatory phosphatase which is predicted to dephosphorylate the site.

Peptide: The predicted dephosphopeptide with 7 amino acids upstream and 7 amino acids downstream around the modified residue.

Score: The value calculated by GPSD algorithm to evaluate the potential of dephosphorylation. The higher the value, the more potential the residue is dephosphorylated.

Cutoff: The cutoff value under the threshold. Different threshold means different precision, sensitivity and specificity.

Source: Whether this dephosphorylation site validated by experiment, "Exp." means YES, while "Pred." means NO. "Exp." links to the source site.

Interaction: Whether the interaction between this substrate and this phosphatase validated by BioGrid, "√" that links to the source PubMed page, means YES, while "--" means NO.

Logo: The sequence logo of this dephosphopeptide.


<2>. The visualization of default prediction

Part 1:
Up: The visualization for the positional distribution of the predicted site in protein sequence. By default, the sites with the highest 3 predicted scores are displayed.
Down: The visualization for protein disordered region predicted by IUPred [PMID: 15955779]. Cutoff = 0.5, if score of prediction > cutoff, the residue is considered in disordered region.

Part 2:
Left: The distribution of S/T/Y sites in phosphatase families.
     The distribution of S/T/Y sites.
     The distribution of S/T/Y sites in disordered region.

Right: The 3D structure of the substrate labeled with predicted dephosphorylation sites.

3. Q: How to choose the cut-off values and the thresholds?

A: Firstly, we calculated the theoretically maximal false positive rate (FPR) for each PPP cluster. The three thresholds of GPSD were decided based on calculated FPRs.For serine/threonine phosphatases, the high, medium and low thresholds were established with FPRs of 2%, 6% and 10%. And for tyrosine phosphatases, the high, medium and low thresholds were selected with FPRs of 5%, 10% and 15%.

 

4. Q: I have a few questions which are not listed above, how can I contact the authors of GPSD?

A: Please contact the major author: Cheng Han, Shanshan Fu, Dr. Di Peng, and Dr. Yu Xue for details.

 

5. Q: Can I use GPSD on different browsers?

A: Yes, we tested our web server on different browsers.

Browser Compatibility
OSVersionChromeFirefoxMicrosoft EdgeSafari
LinuxUbuntu 20.04127.0.6533.119129.0.1N/AN/A
MacOS14.1127.0.6533.120129.0.1N/A17.1
Windows10127.0.6533.120129.0.1127.0.2651.98N/A