This announcement solicits applications for research project grants that will leverage and complement the ongoing technology development being pursued in the National Technology Centers for Networks and Pathways (TCNPs), a program of the NIH Roadmap for Medical Research. These collaborative projects should focus either on addressing a challenging biological problem using the technology developed in one or more of the TCNPs, or on the development of technology that will complement that which is being developed in the centers. Applicants may request support for their own work as well as supplemental support for components pursued in the participating TCNP.