Biochemical Journal Young Investigator Award

Susan Schwab

Susan R. Schwab did her PhD in Nilabh Shastri's lab at the University of California, Berkeley. She is currently a postdoctoral researcher in Jason Cyster's lab at the University of California, San Francisco, where she is studying how sphingosine1-phosphate (S1P) distribution is controlled and how its distribution affects lymphocyte circulation.

Her work has addressed the hypothesis that a S1P gradient between lymphoid organs and circulation is critical to guide lymphocytes out of lymphoid organs. In one study, she showed that S1P lyase expression by haematopoietic cells is critical to keep S1P levels low in the lymphoid organs; disruption of S1P lyase activity increases the S1P concentration in lymphoid organs and inhibits lymphocytes' ability to leave these organs and return to circulation.

In a second study, done in collaboration with Shaun Coughlin's lab, she showed that sphingosine kinase expression by haematopoietic cells, particularly red blood cells, maintains S1P levels high in the blood, and that sphingosine kinase expression by a radiation-resistant cell type maintains S1P high in the lymph. Disruption of sphingosine kinase activity decreases the S1P concentration in circulation and again disrupts lymphocyte exit from lymphoid organs. Taken together, these results suggest that an S1P gradient is essential for lymphocyte circulation.