diff --git a/rest_framework/settings.py b/rest_framework/settings.py
index 312312c9d..d4dc02a24 100644
--- a/rest_framework/settings.py
+++ b/rest_framework/settings.py
@@ -138,7 +138,7 @@ IMPORT_STRINGS = (
     'DEFAULT_METADATA_CLASS',
     'DEFAULT_VERSIONING_CLASS',
     'DEFAULT_PAGINATION_CLASS',
-    'DEFAULT_FILTER_BACKENDS'
+    'DEFAULT_FILTER_BACKENDS',
     'DEFAULT_DB_ROUTER_CLASSES',
     'EXCEPTION_HANDLER',
     'TEST_REQUEST_RENDERER_CLASSES',