PTERIN-4-ALPHA-CARBINOLAMINE DEHYDRATASE 2; PCBD2

Alternative titles; symbols

• DIMERIZATION COFACTOR OF HEPATOCYTE NUCLEAR FACTOR 1-ALPHA 2; DCOH2
• DIMERIZATION COFACTOR OF HEPATOCYTE NUCLEAR FACTOR 1 FROM MUSCLE; DCOHM

HGNC Approved Gene Symbol: PCBD2

Cytogenetic location: 5q31.1 Genomic coordinates (GRCh38): 5:134,905,130-134,962,643 (from NCBI)

▼ Cloning and Expression
Using MIRK (DYRK1B; 604556) as bait in a yeast 2-hybrid screen of a human skeletal muscle cDNA library, Lim et al. (2002) identified PCBD2, which they called DCOHM, encoding a deduced 103-amino acid protein. The DCOHM protein shares 78% sequence identity with DCOH (PCBD1; 126090).

Rose et al. (2004) identified the mouse homolog and determined the high-resolution crystal structure of Dcoh2. Dcoh1 and Dcoh2 dimers adopt the same fold, and their structural differences are confined largely to the protein surfaces and tetramer interface.

▼ Gene Function
Using coimmunoprecipitation studies and GST pull-down assays, Lim et al. (2002) confirmed the interaction of MIRK and DCOHM. DCOH stabilizes HNF1-alpha (142410) as a dimer and enhances its transcriptional activity. Using a reporter gene construct, Lim et al. (2002) showed that DCOHM has a similar activity. In GST pull-down assays, Lim et al. (2002) found that DCOHM, MIRK, and HNF1-alpha form a complex, and that a direct interaction between MIRK and HNF1-alpha can occur in the absence of DCOHM. Lim et al. (2002) concluded that MIRK binds to DCOHM in a DCOHM/HNF1-alpha tetramer, enabling it to bind and phosphorylate HNF1-alpha.

Rose et al. (2004) compared the properties of mouse Dcoh1 with those of Dcoh2. Like Dcoh1, Dcoh2 forms a tetramer, displays pterin-4-alpha-carbinolamine dehydratase activity, and binds Hnf1-alpha in vitro and in vivo. Deletion mutant experiments demonstrated that Dcoh2 binds to the N-terminal dimerization domain of Hnf1-alpha. Unlike the hyperstable Dcoh1 tetramer, Dcoh2 readily disproportionates and forms a 2:2 complex with Hnf1-alpha in vitro. Rose et al. (2004) measured the exchange of monomers in preformed Hnf1-alpha dimers and found that both Dcoh1 and Dcoh2 stabilize Hnf1-alpha dimers.

▼ Mapping
By sequence analysis, Rose et al. (2004) mapped the DCOHM gene to chromosome 5q31.2.