| First Author | Malmberg EK | Year | 2008 |
| Journal | Biochem J | Volume | 410 |
| Issue | 2 | Pages | 283-9 |
| PubMed ID | 17990980 | Mgi Jnum | J:131611 |
| Mgi Id | MGI:3774061 | Doi | 10.1042/BJ20071068 |
| Citation | Malmberg EK, et al. (2008) The C-terminus of the transmembrane mucin MUC17 binds to the scaffold protein PDZK1 that stably localizes it to the enterocyte apical membrane in the small intestine. Biochem J 410(2):283-9 |
| abstractText | The membrane-bound mucins have a heavily O-glycosylated extracellular domain, a single-pass membrane domain and a short cytoplasmic tail. Three of the membrane-bound mucins,MUC3, MUC12 and MUC17, are clustered on chromosome 7 and found in the gastrointestinal tract. These mucins have C-terminal sequences typical of PDZ-domain-binding proteins. To identify PDZ proteins that are able to interact with the mucins,we screened PDZ domain arrays using YFP (yellow fluorescent protein)-tagged proteins. MUC17 exhibited a strong binding to PDZK1 (PDZ domain containing 1), whereas the binding toNHERF1 (Na+/H+-exchanger regulatory factor 1) was weak.Furthermore, we showed weak binding of MUC12 to PDZK1, NHERF1 and NHERF2. GST (glutathione transferase) pull-down experiments confirmed that the C-terminal tail of MUC17 coprecipitates with the scaffold protein PDZK1 as identified byMS. This was mediated through the C-terminal PDZ-interaction site in MUC17, which was capable of binding to three of the four PDZ domains in PDZK1. Immunostaining of wild-type or Pdzk1-/- mouse jejunum with an antiserum against Muc3(17),the mouse orthologue of human MUC17, revealed strong brushborder membrane staining in the wild-type mice compared with an intracellular Muc3(17) staining in the Pdzk1-/- mice. This suggests that Pdzk1 plays a specific role in stabilizing Muc3(17)in the apical membrane of small intestinal enterocytes. |
