Analysis of the cytoplasmic interaction between polycystin-1 and polycystin-2

Abstract

Autosomal dominant polycystic kidney disease (ADPKD) arises following mutations of either Pkd1 or Pkd2. The proteins these genes encode, polycystin-1 (PC1) and polycystin-2 (PC2), form a signaling complex using direct intermolecular interactions. Two distinct domains in the C-terminal tail of PC2 have recently been identified, an EF-hand and a coiled-coil domain. Here, we show that the PC2 coiled-coil domain interacts with the C-terminal tail of PC1, but that the PC2 EF-hand domain does not. We measured the K0.5 of the interaction between the C-terminal tails of PC1 and PC2 and showed that the direct interaction of these proteins is abrogated by a PC1 point mutation that was identified in ADPKD patients. Finally, we showed that overexpression of the PC1 C-terminal tail in MDCK cells alters the Ca2+ response, but that overexpression of the PC1 C-terminal tail containing the disease mutation does not. These results allow a more detailed understanding of the mechanism of pathogenic mutations in the cytoplasmic regions of PC1 and PC2.

Altered trafficking and stability of polycystins underlie polycystic kidney disease

“…In addition, we engi neered 2 experimental truncations, PC1 R4204X and PC1 Y4100X , based on the mouse sequence. The former truncates PC1 before the coiledcoil domain required for interaction with PC2 (52,53); the latter deletes the entire predicted cytoplasmic COOH terminus (33). All 3 truncation mutants showed normal cleavage at the GPS when stably expressed in LLC-PK 1 epithelial cells ( Figure 2D).…”

Polycystin-1: a master regulator of intersecting cystic pathways

“…The working model of polycystin function is that PC1 functions as a mechanosensor or chemosensor at the primary cilium and regulates the activity of the PC2 calcium channel [32] [33] [34]. .…”

Патогенез І Потенційна Терапія Автосомно-Домінантного Полікістозу Нирок

“…Взаимодействие между РС-1 и РС-2 подтверждает важное значение в функционировании Са 2+ -канала. Физически вза-имодействие двух белков осуществляется через их С-терминальный цитоплазматический остаток [18] (рис. 3).…”