Polycystic Kidney And Hepatic Disease 1 Like Protein 1 (PKHD1L1)

The 13,801-bp transcript was amplified by RT-PCR as 16 fragments and sequenced. PKHD1L1 covers a genomic region of 168 kb and encodes a large protein (fibrocystin-L). Fibrocystin-L was predicted to be a large receptor protein (4,243 amino acids; 466 kD) with a signal peptide, single transmembrane domain, and short cytoplasmic tail.

Fibrocystin-L is homologous to fibrocystin throughout most of the extracellular region, with overall identity of 25.0% and similarity of 41.5%. Fibrocystin-L has extracellular domains similar to fibrocystin with 14 copies of the TIG domain and 2 regions of significant homology to the protein TMEM2. The Fugu fish has a fibrocystin-L ortholog but no fibrocystin, suggesting that the newly identified protein may be the ancestral form.