I don't know about any inbuilt function that could achieve this, but you could use a simple Nautilus script:
nautilus "$(dirname "$1")"
In fact, you could even direct Nautilus to the file right away and it would still open the parent directory:
With this script Nautilus will also highlight the file within the directory.
See here for more information on installing Nautilus scripts:
How can I install a Nautilus script?
You could then proceed to set up a shortcut for the script. I'd advise you skip step 2 and 4 of that answer as they don't appear to be necessary. If you named your script something like "Open parent directory" it should be easy to find it in the accels file and change the hotkey. The line should look something like this:
(gtk_accel_path "<Actions>/ScriptsGroup/script_file:\\s\\s\\shome\\sshivshnkr\\s.gnome2\\snautilus-scripts\\sOpen%20parent" "F4")
In this case the shortcut would be F4.