[Frontiers in Bioscience 14, 929-943, January 1, 2009]
Ectoenzymes and innate immunity: the role of human CD157 in leukocyte trafficking
Ada Funaro1,2, Erika Ortolan1,2, Paola Bovino1, Nicola Lo Buono1, Giulia Nacci1, Rossella Parrotta1, Enza Ferrero1,2, Fabio Malavasi1,2
1Department of Genetics, Biology and Biochemistry, and 2Research Center on Experimental Medicine (CeRMS), University of Torino Medical School, Via Santena 19, 10126 Torino, Italy
TABLE OF CONTENTS
CD157 is a glycosylphosphatidylinositol-anchored molecule encoded by a member of the CD38/ADP-ribosyl cyclase gene family, involved in the metabolism of NAD. Expressed mainly by cells of the myeloid lineage and by vascular endothelial cells, CD157 has a dual nature behaving both as an ectoenzyme and as a receptor. Although it lacks a cytoplasmic domain, and cannot transduce signals on its own, the molecule compensates for this structural limit by interacting with conventional receptors. Recent experimental evidence suggests that CD157 orchestrates critical functions of human neutrophils. Indeed, CD157-mediated signals promote cell polarization, regulate chemotaxis induced through the high affinity fMLP receptor and control transendothelial migration.