Are Sakai roles customizable?

My institution requires customizable user roles for students, faculty, and administrative staff that allow for granting of specific permissions to these custom roles, selective release of content to these roles, etc. Different roles will need to have differing levels of access to specific documents, tools, functions, etc. as appropriate. Can Sakai do this?

Yes. Sakai features powerful and flexible support for customizable roles and the granting of fine-grained permissions to those roles. Specific role permissions can be granted over access to specific documents and resources, functionality within tools, etc. Roles can differ across site types and can be further customized within particular sites within Sakai. (In general, a Sakai worksite represents a course or section within a course, but it is possible to create ad-hoc Sakai worksites for other purposes, e.g. collaboration groups. In any case, a user's roles, and the set of roles, can differ across sites.)

See also this article about permissions and roles in Sakai.