PT  - JOURNAL ARTICLE
AU  - Lee, Jungmin
AU  - Vernet, Andyna
AU  - Redfield, Katherine
AU  - Lu, Shulin
AU  - Ghiran, Ionita C.
AU  - Way, Jeffrey C.
AU  - Silver, Pamela A.
TI  - Rational Design of a Bifunctional AND-Gate Ligand to Modulate Cell-Cell Interactions
AID  - 10.1101/711549
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 711549
4099  - http://biorxiv.org/content/early/2019/07/23/711549.short
4100  - http://biorxiv.org/content/early/2019/07/23/711549.full
AB  - Protein “AND-gate” systems, in which a ligand acts only on cells with two different receptors, direct signaling activity to a particular cell type and avoid action on other cells. In a bifunctional AND-Gate protein, the molecular geometry of the protein domains is crucial. Here we constructed a tissue-targeted erythropoietin (EPO) that stimulates red blood cell (RBC) production without triggering thrombosis. EPO was directed to RBC precursors and mature RBCs by fusion to an anti-glycophorin A antibody V region. Many such constructs activated EPO receptors in vitro and stimulated RBC and not platelet production in mice but nonetheless enhanced thrombosis in mice and caused adhesion between RBCs and EPO receptor-bearing cells. Based on a protein-structural model of the RBC surface, we rationally designed an anti-glycophorin/EPO fusion that does not induce cell adhesion in vitro or enhance thrombosis in vivo. Thus, meso-scale geometry can inform design of synthetic-biological systems.