We have reported previously the existence of an Mr 70,000 form of the α6 integrin called α6p in a variety of human epithelial cell lines. Four different experimental conditions were used to examine the regulation of α6 and α6p integrin. The production of the α6 integrin was decreased by 45% using a protein translation inhibitor (2.25 μM puromycin), whereas production of the α6p variant was unaffected. The α6p variant was decreased 60% by actin depolymerization (10 μM cytochalasin D) corresponding to a decrease in its surface expression, whereas α6 integrin production was unaffected. The α6p variant was resistant to endoglycosidase H treatment, whereas the α6 integrin was both sensitive and resistant to endoglycosidase H treatment, indicating retention in the endoplasmic reticulum and processing through the Golgi apparatus. Additionally, digestion by endoglycosidase F demonstrated both α6p and α6 integrin contained NH2-linked glycosylations and both shifted Mr ∼10,000 on enzymatic digestion. Finally, inhibition of serine/threonine phosphatases by either calyculin A (15 nM) or okadaic acid (62 μM) did not affect α6p, whereas the production of α6 integrin was decreased by 50%. These data suggest that the production of the α6p variant is distinct from α6 integrin and may involve a post-translational processing event at the cell surface.
|Original language||English (US)|
|Number of pages||7|
|Journal||Cell Growth and Differentiation|
|State||Published - 2002|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology