Abstract Categorial Grammars (ACG) is a grammatical framework based on linear lambda-calculus. As in Muskens' Lambda Grammars, an abstract term in this kind of categorial grammar can be realized in different directions, such as syntactic and semantic ones. This structure provides autonomy for these different processings. ACG's architecture is independent from the used logic and so the type system is easily extensible in order to deal better with some linguistic phenomena. This paper will be concerned with the issue of overt grammatical movements, in particular extraction constraints in relative propositions, and how several close frameworks deal with it. We will introduce the dependent product construction and show how use it to capture this phenomenon in ACG.