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John K. Northup, Ph.D.

Section on Signal Transduction
Laboratory of Cellular Biology

5 Research Court, Room 2A-11
Rockville, MD 20850
Phone: (301) 496–9167
Fax: (301) 480–8019

Research Statement

The Section on Signal Transduction investigates the molecular bases for G-protein signaling with emphasis on sensory signaling processes. In addition to a diverse array of endocrine and neurotransmitter molecules, G-proteins are now known to mediate the signaling events initiating the visual and chemical senses. In the Signal Transduction Section we utilize recombinant expressed proteins and in vitro biochemical and biophysical assays to examine the selectivity and mechanisms of G-protein signaling at the molecular level. For mechanistic studies we have capitalized on the visual signaling models for G-proteins, since retinal sources provide abundant and homogeneous preparations not only of G-proteins but also their coupled receptors (rhodopsins), effectors (cyclic GMP phosphodiesterase and phospholipase C), and all necessary co-factors for efficient signaling. Using the visual proteins we have devised in vitro assay procedures for each known step in G-protein signaling, and we have adapted these procedures to the analysis of G-protein signaling using recombinant expressed receptors and G-protein subunits. Our current research efforts are applying these approaches to the study of the chemical senses examining the molecular bases for taste, smell, and pheromone detection.

Selected Publications


National Institute on Deafness and Other Communication Disorders. Celebrating 20 years of research: 1988 to 2008