The retirement board shall be deemed to be a state agency within the meaning of chapter 536. Any rule or portion of a rule, as that term is defined in section 536.010, that is created under the authority delegated in sections 86.900 to 86.1280 shall become effective only if it complies with and is subject to all of the provisions of chapter 536 and, if applicable, section 536.028. This section and chapter 536 are nonseverable and if any of the powers vested with the general assembly pursuant to chapter 536 to review, to delay the effective date, or to disapprove and annul a rule are subsequently held unconstitutional, then the grant of rulemaking authority and any rule proposed or adopted after August 28, 2005, shall be invalid and void.