The molecular weight of the heart gap junctional protein subunit was, until recently, believed to be about Mr 28,000-30,000, similar to that of other previously characterized gap junctional proteins. A larger polypeptide of about Mr 44,000-47,000, which undergoes proteolysis during isolation, has recently been proposed as the form of the heart junction protein in vivo. We show here that this entity has the same aminoterminal sequence as the previously characterized Mr 29,000-30,000 component. Thus, the cardiac junctional protein has, at its carboxy-terminus, a cytoplasmic domain of Mr 17,000; this domain is absent in the liver protein. These observations provide further evidence that gap junction proteins form a highly diversified family.
|Original language||English (US)|
|Number of pages||7|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Jan 15 1987|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology