DR. JONATHAN LYTTON

B.Sc. (Calgary), Ph.D. (Harvard) - Professor and Head , Department of Biochemistry & Molecular Biology

Affiliations: Member - Libin Cardiovascular Institute of Alberta.

Research Interests:

The broad subject of investigation in the Lytton laboratory is the control of calcium homeostasis. Calcium ion is a ubiquitous second messenger whose cytoplasmic concentration regulates a host of diverse biological events including muscle contraction, neurotransmitter secretion, hormone signaling, vesicle targeting and cell cycle control. We study proteins that transport calcium across membranes using molecular, biochemical, cellular and physiological techniques to understand structure, function and regulation.

One area of focus concerns the cardiac Na/Ca-exchanger. This plasma membrane transporter plays an essential role in controlling myocyte calcium concentrations during excitation-contraction coupling. The activity of the exchanger is regulated by calcium binding to its large cytoplasmic loop. The mechanism that couples calcium binding to transport activation is currently under investigation.

A second area of focus concerns a family of potassium-dependent Na/Ca-exchangers that are abundant in brain neurons. The unique roles these exchangers play in neuronal physiology is being pursued using recombinant structure-function studies, cell biological analyses, and genetically engineered mice.

Fig.1. HEK293 cells expressing the rat brain potassium-dependent Na/Ca-exchanger, NCKX2, are analyzed using a calcium-sensitive fluorescent indicator dye.

Fig.2. The cardiac Na/Ca-exchanger can be seen localized to the surface of T-tubes in a mouse myocyte using immunofluorescence.

Fig.3. The rat brain potassium-dependent Na/Ca-exchanger, NCKX2, is visualized together with various neuronal markers in cultured hippocampal neurons using dual-dye immunofluroescence at two different magnifications.

Personnel:

View Pub Med for Recent publications & abstracts

Recent Publications:

•  Chandrasekera PC, Kargacin ME, Deans JP, Lytton J. (2009) Determination of apparent calcium affinity for endogenously expressed human sarco/endoplasmic reticulum calcium ATPase isoform, SERCA3. Am J Physiol Cell Physiol. 296: C1105-14.
• Cuomo O, Gala R, Pignataro G, Boscia F, Secondo A, Scorziello A, Pannaccione A, Viggiano D, Adornetto A, Molinaro P, Li, X.-F., Lytton J, Di Renzo G, Annunziato L. (2008) A critical role for the potassium-dependent sodium/calcium exchanger, NCXK2, in protection against Focal Ischemic Brain Damage. J. Neurosci. 28: 2053-2063.
• Visser F, and Lytton J. (2007) K+-dependent Na+/Ca2+-exchanger: key contributors to Ca2+ signaling. Physiology 22: 185-192.
• Lytton J. (2007) Na+/Ca2+-exchangers: three mammalian gene families control Ca2+ transport. Biochem. J. 406: 365-382.
• Visser F, Valsecchi V, Annnziato L, and Lytton J. (2007) Analysis of Ion Interactions with the K+-dependent Na+/Ca2+ exchangers NCKX2, NCKX3 and NCKX4: Identification of T551 as a Key Residue in Defining the Apparent K+ Affinity of NCKX2. J. Biol. Chem. 282: 4453-4462.

Contact Information:

The University of Calgary,
Health Research Innovation Centre - Room GAC64
3280 Hospital Drive NW
Calgary, Alberta 
Canada T2N 4Z6
Phone (403) 220-2893
Fax: (403) 210-8105
E-mail: jlytton [at] ucalgary [dot] ca