Protein Domain : Alpha-2-macroglobulin RAP, domain 3 IPR037999

Type	Domain
Description	This entry is the C-terminal domain (D3) of receptor-associated protein, RAP, also known as alpha-2-macroglobulin receptor-associated protein. RAP is a three domain ER (endoplasmic reticulum)-resident protein that is a chaperone for the LRP (low-density lipoprotein receptor-related protein). RAP is an antagonist and a specialized chaperone that binds tightly to members of the low-density lipoprotein (LDL) receptor family and prevents them from associating with other ligands [ ]. D3 is required for folding and trafficking of low-density lipoprotein receptor-related protein (LRP) [, ]. In the mildly acidic pH of the Golgi, unfolding of RAP-D3 helical bundle facilitates dissociation of RAP from the LDL receptor type A (LA) repeats of LDLR family proteins []. Also, RAP has 3 regions that interact weakly with heparin, two regions located in D3 and one in RAP domain 2 (D2) []. The double module of complement type repeats, CR56, of LRP binds many ligands including alpha2-macroglobulin, which promotes the catabolism of the Abeta-peptide implicated in Alzheimer's disease [].
Short Name	RAP_D3