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Proteomic Mapping Reveals how Lrp2 Interacts with the Endocytic Machine

ABSTRACT: LRP2 (Megalin or Low-density lipoprotein-related receptor 2), together with Cubilin and Amnionless, are responsible for binding and internalizing a wide range of nutrients and toxins from the kidney’s glomerular filtrate by endocytosis. In accordance, Lrp2 deletion or mutation results in loss of these ligands into the urine. Yet Lrp2 is essential not only for receptor-mediated, but also for fluid-phase endocytosis, implicating a broader role beyond ligand binding. To identify the linkage of Lrp2 and endocytosis, we engineered Lrp2-APEX2 expressing mice and performed biotinylation in vivo to label Lrp2’s cytoplasmic partners. We demonstrated the specificity and sensitivity of this technique by mass spectrometric identification of biotinylated proteins from the kidney lysate and by immunostaining kidney sections. We identified critical endocytic regulators interacting with Lrp2, but also many proteins functionally associated with endocytosis but not already known to interact with Lrp2. These data suggest that Lrp2 plays a central role in organizing apical membranes through PDZ domain proteins and engages with regulators and molecular motors during endocytosis. These interactions dissociate in the absence of Lrp2.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Mus Musculus (ncbitaxon:10090)

SUBMITTER: Dr. Thomas A. Neubert Dr. Jonathan Barasch

PROVIDER: MSV000098968 | MassIVE | Thu Aug 28 11:56:00 BST 2025

SECONDARY ACCESSION(S): PXD067851

REPOSITORIES: MassIVE

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