(1) The retirement system shall be construed to be a trust, separate from all other entities, maintained for the purpose of securing payment of benefits to the members, deferred vested members, retirants, and their survivors and beneficiaries as provided in this act.

  (2) The board is the fiduciary of the retirement system with the authority to control and manage the operation and administration of the retirement system in the manner provided by this act.

  (3) This section does not apply to the Tier 2 retirement plan.