The Model Driven Architecture (MDA) promotes the use of models and model transformations for developing software systems. The idea behind MDA is to manage the evolution from Platform Independent Models to Platform Specific Models that can be used to generate executable components and applications. The concepts of metamodels and metamodel-based model transformations are critical in MDA. In this paper, we propose a metamodeling technique to reach a high level of reusability and adaptability of MDA components. In particular, we analyze how to define reusable components for the standard design patterns in a way that fits MDA very closely. To define families of reusable components we describe a “megamodel” that refers to metamodels and model transformations organized into an architectural framework. We propose a “megamodel” formalization that focuses on interoperability of formal languages in Model Driven Development (MDD).