--- a/src/pyams_portal/interfaces/__init__.py	Wed Jun 28 10:16:27 2017 +0200
+++ b/src/pyams_portal/interfaces/__init__.py	Wed Jun 28 11:45:31 2017 +0200
@@ -152,6 +152,8 @@
 
     label = Attribute("Renderer name")
 
+    target_interface = Attribute("Target interface provided by this renderer")
+
 
 class IPortalPortletsConfiguration(IContained):
     """Portal template portlet configuration interface"""

--- a/src/pyams_portal/portlet.py	Wed Jun 28 10:16:27 2017 +0200
+++ b/src/pyams_portal/portlet.py	Wed Jun 28 11:45:31 2017 +0200
@@ -36,7 +36,7 @@
 from pyramid.threadlocal import get_current_registry
 from zope.container.contained import Contained
 from zope.copy import clone
-from zope.interface import implementer
+from zope.interface import implementer, alsoProvides, noLongerProvides
 from zope.lifecycleevent import ObjectCreatedEvent
 from zope.location import locate
 from zope.schema.fieldproperty import FieldProperty
@@ -160,6 +160,8 @@
 class PortletRenderer(PortletContentProvider):
     """Portlet renderer adapter"""
 
+    target_interface = None
+
     @property
     def slot_configuration(self):
         template = IPortalPage(self.context).template
@@ -190,7 +192,7 @@
     """Portlet settings persistent class"""
 
     visible = FieldProperty(IPortletSettings['visible'])
-    renderer = FieldProperty(IPortletSettings['renderer'])
+    _renderer = FieldProperty(IPortletSettings['renderer'])
 
     __name__ = '++settings++'
 
@@ -198,6 +200,26 @@
         self.__parent__ = configuration
 
     @property
+    def renderer(self):
+        return self._renderer
+
+    @renderer.setter
+    def renderer(self, value):
+        value = value or ''
+        if value == self._renderer:
+            return
+        request = check_request()
+        renderer = request.registry.queryMultiAdapter((request.root, request, request, self), IPortletRenderer,
+                                                      name=self._renderer)
+        if (renderer is not None) and (renderer.target_interface is not None):
+            noLongerProvides(self, renderer.target_interface)
+        self._renderer = value
+        renderer = request.registry.queryMultiAdapter((request.root, request, request, self), IPortletRenderer,
+                                                      name=self._renderer)
+        if (renderer is not None) and (renderer.target_interface is not None):
+            alsoProvides(self, renderer.target_interface)
+
+    @property
     def configuration(self):
         return self.__parent__