Fig. 9. Properties of endothelial EndoCL and the associated AM/CGRP receptor system. (I) Endothelial EndoCL is expressed on the cell surface as a mature glycoprotein (N-linked carbohydrate residues are schematically represented as grey boxes). Both AM and CGRP induce Akt phosphorylation (Akt-P). (IIA) Receptor is internalised and (III) targeted for degradation upon activation by AM, but (IIB) remains at the cell surface after interaction with CGRP. Interaction with either AM (I-IIA-III) or CGRP (I-IIB) results in (IV) desensitisation of the receptor to both peptides, irrespective of which agonist was used for initial stimulation, and a loss of activity through distinct alternative mechanisms.