Through interactions with one of its ligands, reelin, ApoER2 plays an important role in embryonic neuronal migration and postnatal long-term potentiation.

ApoER2 is distinct from most other members of the LDL family of receptors due to a unique insert on its cytoplasmic tail.

It binds the PSD-95 adapter protein, cross-linking ApoER2 and the NMDA receptors during the process of long-term potentiation, and is also bound specifically by JIP-2, an important interaction in the JNK signalling pathway.

[10] This pathway specifically affects cortical migration and long-term potentiation.In development, reelin is secreted by Cajal-Retzius cells.

This transduction is combined with the activation of other pathways that influence the cytoskeletal rearrangement necessary for proper cortical cell migration.

Such abnormal layering is also seen in VLDLR−apoER2− and dab1- mutants, indicating the importance of this entire pathway in cortical migration of the developing embryo.

These conflicting results have led researchers to speculate that it plays a role in both processes through interactions with different molecules at different stages of neuronal migration.

Through binding of ApoER2 in the hippocampus, it plays a role in the NMDA receptor activation that is required for long-term potentiation, a mechanism by which two neurons gain a stronger, longer-lasting transmission due to simultaneous firing.

This occurs through Dab-1 activation of Src family kinases, which have been shown to play a role in regulating synaptic plasticity.

[10] ApoER2 plays a more important role in this process, most likely due to its ability to bind the PSD-95 adapter protein through the 59 amino acid insert on its cytoplasmic tail.

[9] Selenoprotein P transports the trace element selenium from the liver to the testes and brain, and binds to ApoER2 in these areas.

Mice that have had their ApoER2 or Selenoprotein P expression knocked out show impaired spermatozoa development and decreased fertility.

An example of a decrease in expression of LRP8 is when gamma secretase cleaves LRP8 as well as the ligand amyloid precursor protein (APP).

[14] The presence of amyloid beta (Aβ) protein deposits in neuronal extracellular space is one of the hallmarks of Alzheimer's disease.

In addition, the expression of ApoER2 within intracellular compartments leads to increased gamma secretase activity, a protease which works to cleave APP into Aβ.

Reduced reelin signaling leads to impaired plasticity in neurons and increases in the phosphorylation of tau protein, which is a microtubule stabilizing protein that is abundant in the Central Nervous System (CNS), producing neurofibrillary tangles which are implicated in Alzheimer's disease.

[18] Antiphospholipid syndrome is an autoimmune disease characterized by thrombosis and complications during pregnancy, often leading to fetal death.

There is also speculation that the antibody/β2GPI complexes sensitize other cell types through various LDL family receptors to lead to less common symptoms other than thrombosis.

Loss of ApoER2 results in insufficient selenium levels, leading to failed translation of the key ferroptosis regulator and selenoprotein GPX4.

[20] Reduced expression of ApoER2 in peripheral blood lymphocytes can contribute to major depressive disorder (MDD) in some patients.