Juxtacrine signaling

Juxtacrine signaling is a special case of the paracrine mode in which a growth factor displayed on the surface of one cell binds to a receptor on a neighboring cell. 

Singh AB, Harris RC. Autocrine, paracrine, and juxtacrine signaling by EGFR ligands. Cell Signal 2005 17 1183-1193. 

A chemical messenger may be defined as autocrine (affects the same ceU that synthesises it), paracrine (affects a nearby target cell), intracrine (acts within the cell (e.g. steroid hormones)) or juxtacrine (signals are transmitted along cell membranes via protein or lipid components integral to the membrane and are capable of affecting either the emitting cell or cells immediately adjacent). 

NOTCH proteins participate in conserved pathways that regulate cellular differentiation, proliferation, and cell death. Mammalian NOTCH receptors are single-pass transmembrane proteins that transmit juxtacrine signals initiated by ligands of the Delta, Serrate, or Lag-2 family [122, 123], When ligands bind to the extracellular domain of NOTCH1, sequential proteolytic processing events lead to the... 

PAF is synthesized by platelets, neutrophils, monocytes, mast cells, eosinophils, renal mesangial cells, renal medullary cells, and vascular endothelial cells. PAF is released from monocytes but retained by leukocytes and endothelial cells. In endothelial cells, it is displayed on the surface for juxtacrine signaling. 

Bosenberg, M. W. and Massague, J. (1993). Juxtacrine cell signaling molecules. Curr. Opin. Cell Biol. 5, 832-838. 

---