SorLA: ProductsSorLA (Sorting protein-related receptor containing LDLR class A repeats; also LR11 and SorL1) is a 250 - 330 kDa, monomeric member of the SORL1 family of proteins. It is expressed on the cell surface (10%) and in Golgi/ER membranes (90%) of neurons and vascular smooth muscle cells. SorLA binds apoE-rich lipoproteins plus the 39 kDa RAP. It also acts as an intracellular sorting receptor for APP. In this context, it blocks transport of APP into compartments that exhibit beta-secretase activity, thus interfering with A beta peptide generation. Human SorLA is a type I transmembrane glycoprotein 2214 amino acids (aa) in length. It contains a 28 aa signal sequence, a 53 aa propeptide, and a 2133 aa mature molecule. The mature molecule contains a 2056 aa extracellular domain (ECD) (aa 82 - 2137) and a short 56 aa cytoplasmic tail. The ECD is highly modular, containing five BNR/Asp-box repeats (aa 136 - 573), five LDLR class B repeats (aa 800 - 1013), one EGF-like domain (aa 1026 - 1072), 11 LDLR class A domains (aa 1076 - 1551) and six FN type III repeats (aa 1554 - 2023). Multiple potential splice variants exist. There are alternative start sites at Met1057 and Met1155, plus a 63 aa substitution for aa 1 - 1153 and a 19 aa substitution for aa 1 - 1404. Over aa 82 - 367, human SorLA shares 93% aa identity with mouse SorLA.