1. Proteins are concentrated to a region of the cell (i.e., apical membrane, myoendothelial junction) and altogether participate in a specific cellular function. | Exocytosis at the apical membrane (section IV) |
Endothelium-dependent hyperpolarization-mediated response (section III.C) |
2. There is an accumulation of two or more proteins contained within a membranous phospholipid region (i.e., lipid raft, caveolae), and the loss of this structure alters cell-cell communication. | eNOS localized in caveolae (section II.A) |
3. There is a direct protein-protein interaction, and disruption of this interaction alters cell-cell communication. | eNOS and caveolin 1 (section II.A.1) |
eNOS and Hbα (section II.A.4) |
Cx43 and ZO-1 (section III.A.4) |
4. There is evidence for close localization of proteins, with a loss of one of the proteins (function or expression) altering the way in which cell-cell communication occurs. | Endothelium-dependent hyperpolarization-mediated response (section III.A) |