Regulation of Sialomucin Complex Expression and its Effect on HER Receptor Interaction
Abstract
Sialomucin complex (SMC) is a heterodimeric glycoprotein complex consisting of a mucin subunit ASGP-1 (ascites sialoglycoprotein-1) and a transmembrane subunit ASGP-2, which can act as a ligand for the receptor tyrosine kinase ErbB2. SMC is a highly expressed protein on the surface of ascites 13762 rat mammary adenocarcinoma cells, approximately 102 times the level in lactating mammary gland and 10(exp 4) times that in virgin mammary gland. SMC is largely post-transcriptionally regulated in developing mammary gland. SMC can be post-transcriptionally regulated in normal cultured rat mammary epithelial cells (MEC) but not 13762 ascites tumor cells by Matrigel by inhibition of SMC precursor synthesis. SMC is also post-translationally regulated by TGF-beta by inhibition of SMC precursor processing into mature ASGP-1 and ASGP-2. Interestingly, SMC levels in 13762 ascites tumor cells are unaffected by TGF-beta. SMC and ErbB-2 have similar expression patterns in normal developing mammary gland and can be found in a complex in virgin as well as lactating mammary tissue. Thus, SMC is regulated by two novel post-transcriptional mechanisms in normal mammary epithelial cells but not 13762 tumor cells and its complex formation with the receptor ErbB-2 may play some role in mammary development and differentiation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2000
- Accession Number
- ADA390702
Entities
People
- Kermit Carraway
- Nebila Idris
Organizations
- University of Miami