# Interactions, Feature-Level

## Overview
The Interactions Tab provides experimentally and computationally derived host-pathogen protein-protein interaction data and visualizations from more than 15 public repositories, including [STRINGDB](https://string-db.org/), with a total of 55 million protein-protein interactions. Interactions are available at both the genome and feature levels, and are presented in tabular and graph format.

## See also
  * [Interactions Tab, Taxon/Genome-Level](/quick_references/organisms_taxon/interactions)

## Accessing the Feature-Level Interactions Table
Clicking the Interactions Tab in a Feature View displays the Interactions Table, listing of all of the interactions associated with that feature.

![Interactions Table, Feature-Level](../images/interactions_table_feature.png)

The tables include the following columns (fields) for each interaction, and are based on [PSI-MITAB](https://wiki.reactome.org/index.php/PSI-MITAB_interactions) format:

* **Interactor A:** ID (unique primary identifier) for one of the two interacting features (protein-coding genes).
* **Gene A:** Gene name for the feature, if available.
* **Desc A:** Protein product (functional annotation) associated with the feature.  
* **Interactor B:** ID for the other of the two interacting features.
* **Gene B:** Gene name for the feature, if available.
* **Desc B:** Protein product associated with the feature.  
* **Category:** Category of interaction: 
   * PPI = protein-protein interaction
   * HPI = host-pathogen interaction
* **Interaction Type:** Interaction types, taken from the corresponding [PSI-MI controlled vocabulary](https://www.ebi.ac.uk/ols/ontologies/mi).
* **Detection Method:** Interaction detection method, taken from the corresponding [PSI-MI controlled vocabulary](https://www.ebi.ac.uk/ols/ontologies/mi).
* **Evidence:** Evidence of the interaction:
  * Experimental = identified by laboratory method
  * Computational = predicted by computational method 

## Interactions Table

### Action buttons

After selecting a feature by clicking the checkbox beside row on the left side of the table, a set of options becomes available in the vertical green Action Bar on the right side of the table.  These include

* **Hide/Show:** Toggles (hides) the right-hand side Details Pane.
* **Download:**  Downloads the selected items (rows).
* **Copy:** Copies the selected items to the clipboard.
* **Features:** Loads the Features Table for the features corresponding to the selected interaction.
* **FASTA:** Provides the FASTA DNA or protein sequence for the selected feature(s).
* **Group:** Opens a pop-up window to enable adding the selected sequences to an existing or new group in the private workspace.

More details are available in the [Action Buttons](/quick_references/action_bar) Quick Reference Guide.

## Interactions Viewer
Clicking the **Graph** option at the top left of the table displays the [Cytoscape](http://www.cytoscape.org/)-based Interactions Viewer. 

![Interactions Viewer](../images/interactions_viewer_feature.png)

In the graph, proteins (interactors) are displayed as nodes and the interactions between the nodes are displayed as lines. Scrolling with the mouse zooms in/out in the graph.  Clicking and dragging with the mouse moves the graph in the display. Gene names, where available, are displayed on the nodes. Mousing over a node or line displays detailed information about that interactor/interaction. Clicking and dragging on a node moves it in the graph, allowing rearrangement for better visualization.

Additional options are available from the upper right area of the graph.  These include the following:

* **Export:** Creates a png image file of the graph and makes it available for saving to disk.
* **Subgraph:** Auto-selects subgraphs with more than 5, 10, or 20 nodes, or auto-selection of the largest subgraph.
* **Hub Protein:** Auto-selects hub proteins with more than 5, 10, or 20 nodes, or auto-selection of the most connected hub 
* **Layout:** Changes the layout of the display, with several options available
### Action buttons

After selecting one or more of the nodes by clicking it (ctrl-clicking to select multiple nodes), a set of options becomes available in the vertical green Action Bar on the right side of the table.  These include

* **Hide/Show:** Toggles (hides) the right-hand side Details Pane.
* **Download:**  Downloads the selected items (rows).
* **Copy:** Copies the selected items to the clipboard.
* **Feature:** Loads the Feature Page for the selected feature. *Available only if a single feature is selected.*
* **Features:** Loads the Features Table for the selected features. *Available only if multiple features are selected.*
* **FASTA:** Provides the FASTA DNA or protein sequence for the selected feature(s).
* **MSA:** Launches the Multiple Sequence Alignment (MSA) tool and aligns the selected features by DNA or protein sequence in an interactive viewer.
* **Group:** Opens a pop-up window to enable adding the selected sequences to an existing or new group in the private workspace.

More details are available in the [Action Buttons](/quick_references/action_bar) Quick Reference Guide.