Abstract
Sialomucin complex (SMC, Rat Muc4) 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 highly expressed on the surface of ascites 13762 rat mammary adenocarcinoma cells, approximately 100 times the level in lactating mammary gland and 104 times that in virgin mammary gland. SMC is sharply increased at mid-pregnancy in a manner similar to β-casein. Unlike β-casein, SMC appears to be regulated post-transcriptionally. Its transcript is present in both virgin and pregnant mammary tissue, and SMC synthesis is induced rapidly in cultured primary mammary epithelial cells from either normal pregnant or virgin rats. SMC protein, but not transcript, levels are significantly reduced when mammary cells are cultured in Matrigel, a reconstituted basement membrane which stimulates casein expression. SMC precursor is synthesized in Matrigel at a 10-fold lower rate. Matrigel has no effect on either the level of SMC or its transcript in cultured 13762 mammary tumor cells. The Matrigel effect on primary mammary and 13762 cells is mimicked by transforming growth factor β, a component associated with this complex matrix. These results indicate that SMC is a novel product of normal mammary gland and milk, which is post-transcriptionally regulated by transforming growth factor β in normal mammary gland, but not in 13762 mammary adenocarcinoma cells.
| Original language | English |
|---|---|
| Pages (from-to) | 35228-35237 |
| Number of pages | 10 |
| Journal | Journal of Biological Chemistry |
| Volume | 273 |
| Issue number | 52 |
| DOIs | |
| State | Published - Dec 25 1998 |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Post-transcriptional regulation of a milk membrane protein, the sialomucin complex (ascites sialoglycoprotein (ASGP)-1/ASGP-2, Rat Muc4), by transforming growth factor β. / Price-Schiavi, Shari A.; Carothers Carraway, Coralie A.; Fregien, Nevis L.; Carraway, Kermit L.
In: Journal of Biological Chemistry, Vol. 273, No. 52, 25.12.1998, p. 35228-35237.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Post-transcriptional regulation of a milk membrane protein, the sialomucin complex (ascites sialoglycoprotein (ASGP)-1/ASGP-2, Rat Muc4), by transforming growth factor β
AU - Price-Schiavi, Shari A.
AU - Carothers Carraway, Coralie A.
AU - Fregien, Nevis L.
AU - Carraway, Kermit L.
PY - 1998/12/25
Y1 - 1998/12/25
N2 - Sialomucin complex (SMC, Rat Muc4) 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 highly expressed on the surface of ascites 13762 rat mammary adenocarcinoma cells, approximately 100 times the level in lactating mammary gland and 104 times that in virgin mammary gland. SMC is sharply increased at mid-pregnancy in a manner similar to β-casein. Unlike β-casein, SMC appears to be regulated post-transcriptionally. Its transcript is present in both virgin and pregnant mammary tissue, and SMC synthesis is induced rapidly in cultured primary mammary epithelial cells from either normal pregnant or virgin rats. SMC protein, but not transcript, levels are significantly reduced when mammary cells are cultured in Matrigel, a reconstituted basement membrane which stimulates casein expression. SMC precursor is synthesized in Matrigel at a 10-fold lower rate. Matrigel has no effect on either the level of SMC or its transcript in cultured 13762 mammary tumor cells. The Matrigel effect on primary mammary and 13762 cells is mimicked by transforming growth factor β, a component associated with this complex matrix. These results indicate that SMC is a novel product of normal mammary gland and milk, which is post-transcriptionally regulated by transforming growth factor β in normal mammary gland, but not in 13762 mammary adenocarcinoma cells.
AB - Sialomucin complex (SMC, Rat Muc4) 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 highly expressed on the surface of ascites 13762 rat mammary adenocarcinoma cells, approximately 100 times the level in lactating mammary gland and 104 times that in virgin mammary gland. SMC is sharply increased at mid-pregnancy in a manner similar to β-casein. Unlike β-casein, SMC appears to be regulated post-transcriptionally. Its transcript is present in both virgin and pregnant mammary tissue, and SMC synthesis is induced rapidly in cultured primary mammary epithelial cells from either normal pregnant or virgin rats. SMC protein, but not transcript, levels are significantly reduced when mammary cells are cultured in Matrigel, a reconstituted basement membrane which stimulates casein expression. SMC precursor is synthesized in Matrigel at a 10-fold lower rate. Matrigel has no effect on either the level of SMC or its transcript in cultured 13762 mammary tumor cells. The Matrigel effect on primary mammary and 13762 cells is mimicked by transforming growth factor β, a component associated with this complex matrix. These results indicate that SMC is a novel product of normal mammary gland and milk, which is post-transcriptionally regulated by transforming growth factor β in normal mammary gland, but not in 13762 mammary adenocarcinoma cells.
UR - http://www.scopus.com/inward/record.url?scp=0032567357&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032567357&partnerID=8YFLogxK
U2 - 10.1074/jbc.273.52.35228
DO - 10.1074/jbc.273.52.35228
M3 - Article
C2 - 9857062
AN - SCOPUS:0032567357
VL - 273
SP - 35228
EP - 35237
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 52
ER -