Identification of a Polycystin-1 Cleavage Product, P100, That Regulates Store Operated Ca2+ Entry through Interactions with STIM1
Figure 1
Biochemical characterization of a novel endogenous polycystin-1 product, P100.
(A) Pkd1 alleles and schematic diagram of their corresponding polycystin-1 proteins. Pkd1HA is a 3xHA-tagged Pkd1 knock-in allele that produces fully functional PC1 protein. The domains in polycystin-1 are shown. Anti-CC is directed to the cytoplasmic C-terminal tail. The position of uncleaved full-length (uFL), the C-terminal (CTF) and the P100 product is schematically shown. (B) Western blots for wild-type embryo (E18.5), lung (Bi), and kidney (Bii and iii) at different postnatal stages as indicated using anti-CC antibodies after immunoprecipitation. Western blot shown in Bii (enclosed by dashed box) originally from Yu et al 2007; © 2007 by The National Academy of Sciences of the USA. The bands corresponding to uFL, CTF and P100 are indicated. * indicates a band of unknown nature in the lung. (C) Western blot for postnatal kidneys from PKD1v/v mice. (D) Western blot from mouse embryonic fibroblasts (MEF) isolated from Pkd1HA/HA and wild-type 11.5 day old embryos using anti-HA antibody after immunoprecipitation or on the whole cell lysate. (E) Western blot for homozygous Pkd1HA/HA tissues at P20 using anti-HA antibody after immunoprecipitation. The lung of the wild-type littermate (+/+) serves as a negative control.