PUBLICATION

IPIP27A cooperates with OCRL to support endocytic traffic in the zebrafish pronephric tubule

Authors
Oltrabella, F., Jackson-Crawford, A., Yan, G., Rixham, S., Starborg, T., Lowe, M.
ID
ZDB-PUB-211025-15
Date
2021
Source
Human molecular genetics   31(8): 1183-1196 (Journal)
Registered Authors
Lowe, Martin, Yan, Guanhua
Keywords
IPIP27OCRLLowe syndromezebrafishkidney
MeSH Terms
  • Animals
  • Endocytosis/genetics
  • Endosomes/genetics
  • Endosomes/metabolism
  • Female
  • Humans
  • Inositol Phosphates/metabolism
  • Kidney Tubules, Proximal/metabolism
  • Low Density Lipoprotein Receptor-Related Protein-2/genetics
  • Low Density Lipoprotein Receptor-Related Protein-2/metabolism
  • Male
  • Oculocerebrorenal Syndrome*/genetics
  • Oculocerebrorenal Syndrome*/metabolism
  • Phosphoric Monoester Hydrolases/genetics
  • Phosphoric Monoester Hydrolases/metabolism*
  • Proteins/metabolism
  • Zebrafish/genetics
  • Zebrafish/metabolism
  • Zebrafish Proteins/metabolism*
PubMed
34673953 Full text @ Hum. Mol. Genet.
Abstract
Endocytosis is a fundamentally important process through which material is internalized into cells from the extracellular environment. In the renal proximal tubule, endocytosis of the abundant scavenger receptor megalin and its co-receptor cubilin play a vital role in retrieving low molecular weight proteins from the renal filtrate. Although we know much about megalin and its ligands, the machinery and mechanisms by which the receptor is trafficked through the endosomal system remain poorly defined. In this study, we show that Ipip27A, an interacting partner of the Lowe syndrome protein OCRL, is required for endocytic traffic of megalin within the proximal renal tubule of zebrafish larvae. Knockout of Ipip27A phenocopies the endocytic phenotype seen upon loss of OCRL, with a deficit in uptake of both fluid-phase and protein cargo, which is accompanied by a reduction in megalin abundance and altered endosome morphology. Rescue and co-depletion experiments indicate that Ipip27A functions together with OCRL to support proximal tubule endocytosis. The results therefore identify Ipip27A as a new player in endocytic traffic in the proximal tubule in vivo and support the view that defective endocytosis underlies the renal tubulopathy in Lowe syndrome and Dent-2 disease.
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