When I try to run mypaint from terminal I get this:

~ $ mypaint
Traceback (most recent call last):
File "/usr/bin/mypaint", line 123, in <module>
from gui import main
File "/usr/share/mypaint/gui/main.py", line 15, in <module>
from gui import application
File "/usr/share/mypaint/gui/application.py", line 14, in <module>
import filehandling, keyboard, brushmanager
File "/usr/share/mypaint/gui/filehandling.py", line 18, in <module>
from lib import document, helpers
File "/usr/share/mypaint/lib/document.py", line 17, in <module>
import command, stroke, layer
File "/usr/share/mypaint/lib/command.py", line 9, in <module>
import layer
File "/usr/share/mypaint/lib/layer.py", line 11, in <module>
import tiledsurface, strokemap, strokemap_pb2
File "/usr/share/mypaint/lib/strokemap.py", line 13, in <module>
import tiledsurface, idletask, strokemap_pb2
File "/usr/share/mypaint/lib/strokemap_pb2.py", line 3, in <module>
from google.protobuf import descriptor
ImportError: No module named google.protobuf

What is google.protobuf? The previous version 0.7.1 worked properly. I now have the newest version (just updated)
liblapack3gfs seems to be installed.
Anything I could have missed?