In this paper we address the problem of the combined representation of heterogeneous sources of knowledge within a unique and homogeneous data structure. The goal is ultimately to enable the holistic processing of linguistic and world knowledge, where all the dimensions may interact seamlessly. We focus here on bridging the gap between Syntax and Semantics. We propose to link an abstract grammar to an existing lexical network through the adoption of the same underlying graph structure. The resulting structure may be seen as a multi-layer linguistic network. The solution we introduce for the abstract grammar layer relies on a graph-theoretic interpretation of Property Grammar. The typed structure we propose supersedes both phrase structure and dependency structure, which are covered with specific relation types-Constituency and Dependency respectively. We present a procedure to derive the grammar from an annotated corpus, and we illustrate the procedure with the French Treebank.