Podocyte polarity signalling.
OBJECTIVE
The glomerular filtration barrier is a unique structure characterized by a specialized three-dimensional framework of podocytes. This review is aimed at describing the latest advances made in the understanding of polarity signalling pathways regulating the formation and the maintenance of the complex podocyte architecture.


RESULTS
Podocytes are composed of a large cell body that extends primary and secondary processes. An apicobasal polarity axis allows for podocyte orientation between the urinary space and the glomerular basement membrane. Recent studies document that conserved polarity protein complexes such as the partitioning defective 3 (Par3), partitioning defective 6 (Par6) and atypical protein kinase C (aPKC) complex are essential regulators of podocyte morphology. Glomerular development, slit diaphragm targeting and apicobasolateral distribution of molecules seem to be tightly regulated by these polarity signalling pathways.


CONCLUSIONS
Accumulating evidence indicates that conserved polarity protein complexes are essential for normal podocyte morphology and differentiation. The diseased podocyte, which typically presents with foot process effacement, might require these molecular guideposts when recovering from stress and when restoring normal podocyte morphology.
Simons
Matias
M
Renal Division, University Hospital Freiburg, Freiburg, Germany.
Hartleben
Björn
B
Huber
Tobias B
TB
D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology; D000818:Animals; D018797:Cell Cycle Proteins / Q000502:physiology; D002454:Cell Differentiation; D016764:Cell Polarity / Q000502:physiology*; D048430:Cell Shape; D006801:Humans; D007678:Kidney Glomerulus / Q000196:embryology; D008565:Membrane Proteins / Q000502:physiology; D009024:Morphogenesis; D050199:Podocytes / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000502:physiology
D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D008565:Membrane Proteins; C509689:PARD3 protein, human; C499657:PARD6A protein, human; D016212:Transforming Growth Factor beta; D011493:Protein Kinase C