updating MembershipUser's email and IsApproved status and Email

Hi,
I'm working on a screen for an admin to update user profile information, such as their Email and IsApproved status.  I'm able to get the user, but the below does not seem to be updating anything:
            MembershipUser currentUser = Membership.GetUser(userId);

            if (currentUser != null)
            {
                currentUser.Email = txtEmail.Text;
                currentUser.IsApproved = chkIsApproved.Checked;

                if (!chkLockedOut.Checked)
          &n ...