diff --git a/rest_framework_fine_permissions/utils.py b/rest_framework_fine_permissions/utils.py
index <HASH>..<HASH> 100644
--- a/rest_framework_fine_permissions/utils.py
+++ b/rest_framework_fine_permissions/utils.py
@@ -23,7 +23,7 @@ def inherits_modelpermissions_serializer(cls):
 
 def get_model_fields(model):
     fields_info = get_field_info(model)
-    return chain(iterkeys(fields_info.fields_and_pk),
+    return chain(iterkeys(fields_info.fields),
                  iterkeys(fields_info.relations))
bug correction: replace fields_and_pk by fields