The poly-proline motifs found in the cytoplasmic tail of the brush border cadherin CDHR5 play a role in its ability to elongate microvilli.

Cadherin-related family member 5 (CDHR5) is a protocadherin found enriched at the tips of brush border microvilli of the gut and kidney, where it plays an important role in the development of these specialized microvilli. CDHR5 is a type-1 transmembrane protein with a short cytoplasmic tail that contains a number of poly-proline motifs of unknown function. We performed an analysis of the poly-proline stretches in the CDHR5 cytoplasmic tail and show that mutation of these motifs does not largely influence the targeting of CDHR5 to microvilli, but does significantly impact the ability of the cadherin to promote microvillar elongation.