Department of Physiology, Development and Neuroscience

Reader in Cell Physiology, Fellow of Selwyn College
Tel: 01223 333870, Fax: +44 (0)1223 333840, E-mail: sos10@cam.ac.uk

I am a Reader in Cell Physiology and give courses on Renal Physiology and Body Fluid Homeostasis in IA MVST Homeostasis, IA NST Physiology of Organisms, IB NST Physiology and in Module 13 of Part II Physiology, Development & Neuroscience. I also contribute lectures on Store-Mediated Calcium Entry to Module 6 of the Part II PDN course.

(Fig. Confocal image of human platelets showing the actin cytoskeleton stained with FITC-labelled phalloidin, by Juan Rosado and Austin Hockaday)

I serve on the Editorial Board of Cell Calcium and am a past Chairman of the Editorial Board of the Journal of Physiology.

I am a Fellow of Selwyn College, where I am Director of Studies in Biological Natural Sciences. I am also a Director of Studies in Medicine at Magdalene College. I supervise in IA MVST Homeostasis, IA NST Physiology of Organisms, IB MVST Human Reproduction and IB NST Physiology.

Other than Physiology, I am interested in music, real ale and tiddlywinks. I am Senior Treasurer of CU Concert Band and CU Tiddlywinks Club. I am Vice-Chairman of the English Tiddlywinks Association and an Associate of the London College of Music in trombone playing.

Research Interests
My group is interested in intracellular calcium signalling mechanisms and the role of calcium signals in platelet and endothelial cell function.

In platelets, we work on the mechanisms which generate calcium entry and in particular on the mechanisms which couple the depletion of the intracellular calcium store to the activation of calcium entry. This work involves platelet populations and employs fluorecent indicators and protein chemistry. We collaborate with Dr Juan Rosado and colleagues at the University of Extremadura and with Dr Johan Heemskerk and others at the University of Maastricht.

Publications
2006

Redondo, P.C., Harper, M.T., Rosado, J.A. & Sage, S.O. (2006). A role for cofilin in the activation of store-operated calcium entry by de novo conformational coupling in human platelets. Blood 107, 973-979.

Harper, M.T. & Sage, S.O. (2006). Actin polymerisation regulates thrombin-evoked Ca²⁺ signalling after activation of PAR-4 but not PAR-1 in human platelets. Platelets 17, 134-142.

Harper, A.G.S. & Sage, S.O. (2006). A role for the intracellular protease calpain in the activation of store-operated calcium entry in human platelets. Cell Calcium (in press). E-pub ahead of print: doi:10.1016/j.ceca.2006.05.008.

Cauwenberghs, S., Feijge, M.A., Harper, A.G.S., Sage, S.O., Curvers, J. & Heemskerk, J.W.M. (2006). Shedding of procoagulant microparticles from unstimulated platelets by integrin-mediated destabilization of actin cytoskeleton. FEBS Letters 580, 5313-5320.

Harper, M.T. & Sage, S.O. (2006). PAR-1–dependent pp60src activation is dependent on protein kinase C and increased [Ca²⁺]i: evidence that pp60src does not regulate PAR-1–dependent Ca²⁺ entry in human platelets. Journal of Thrombosis and Haemostasis (in press).

2005

Rosado JA, Redondo PC, Salido GM, Sage SO & Pariente JA (2005). Cleavage of SNAP-25 and VAMP-2 impairs store-operated Ca²⁺ entry in mouse pancreatic acinar cells. American Journal of Physiology 288, C214-C221.

Brownlow, S.L. & Sage, S.O. (2005). Transient receptor potential protein subunit assembly and membrane distribution in human platelets. Thrombosis and Haemostasis 94, 839-845.

Rosado, J.A., Redondo, P.C., Sage, S.O., Pariente, J.A. & Salido, G.M. (2005). Store-operated Ca²⁺ entry: Vesicle fusion or reversible trafficking and de novo conformational coupling? Journal of Cell Physiology 205, 206-209.

2004

Brownlow, S.L., Harper, A.G.S., Harper, M.T. & Sage, S.O. (2004). A role for hTRPC1 and lipid raft domains in store-mediated calcium entry in human platelets. Cell Calcium 35, 107-113.

Rosado, J.A., Redondo, P.C., Salido, G.M., Gomez-Arteta, E., Sage, S.O. & Pariente. J.A. (2004). Hydrogen peroxide generation induces pp60src activation in human platelets. Evidence for the involvement of this pathway in store-mediated calcium entry. Journal of Biological Chemistry 279, 1665-1675.

Redondo, P.C., Harper, A.G.S., Salido, G.M., Pariente, J.A., Sage, S.O. and Rosado, J.A. (2004). A role for SNAP-25 but not VAMP in store-mediated Ca²⁺ entry in human platelets. Journal of Physiology 558, 99-109.

Rosado, J.A., Lopez, J.J., Harper, A.G.S., Harper, M.T., Redondo, P.C., Pariente, J.A., Sage, S.O. and Salido, G.M. (2004). Two pathways for store-mediated calcium entry differentially dependent on the actin cytoskeleton in human platelets. Journal of Biological Chemistry 279, 29231-29235.

2003

Brownlow, S.L. & Sage, S.O. (2003). Rapid agonist-evoked coupling of the type II inositol 1,4,5-trisphosphate receptor to human transient receptor potential (hTRPC1) channels in human platelets. Biochemical Journal 375, 697-704.

2002

Rosado, J.A., Brownlow, S.L. & Sage, S.O. (2002). Endogenously expressed Trp1 is involved in store-mediated calcium entry in human platelets. Journal of Biological Chemistry 277, 42157-42163.

van Gestel1, M.A., Heemskerk, J.W.M., Slaaf, D.W., Heijnen, V.V.T., Sage, S.O., Reneman, R.S. & oude Egbrink, M.G.A. (2002). Real-time detection of activation patterns in individual platelets during thromboembolism in vivo: differences between thrombus growth and embolus formation. Journal of Vascular Biology 39, 234-243.

Rosado, J.A. & Sage, S.O. (2002). The ERK cascade, a new pathway involved in the activation of store-mediated calcium entry in human platelets. Trends in Cardiovascular Medicine 12, 229-234.