I've found the solution!
The problem was that in QT4 there are a signal and a slot with the same name - currentChanged(QModelIndex, QModelIndex)
To obtain an index of current cell while moving through the table we have to add a selectionModel to our TableView:
selectionModel = QtGui.QItemSelectionModel(TableView.model())
connect(selectionModel, QtCore.SIGNAL("currentChanged(QModelIndex, QModelIndex)"), some_function)
Et voila, it works!