How to get all values for a given key in a nested structure in clojure

(def threads
  {:values
   [{:_id "t1"
     :u {:uid 1}
     :members {:values [{:uid 1} {:uid 2}]}
     :messages {:values
                [{:_id "m1" :u {:uid 1}}
                 {:_id "m2" :u {:uid 2}}]}}
    {:_id "t2"
     :u {:uid 12}
     :members {:values [{:uid 11} {:uid 12}]}
     :messages {:values
                [{:_id "m3" :u {:uid 13}}
                 {:_id "m4" :u {:uid 12}}]}}]})

Need to find out all values for the key :uid In this case answer should return [1 2 11 12 13] without using any global bindings. Needs solution scale for any level of nested structure.

Thanks