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In vitro proteolysis of brain spectrin by calpain I inhibits association of spectrin with ankyrin-independent membrane binding site(s).
| Content Provider | Semantic Scholar |
|---|---|
| Author | Hu, Rona J. Bennett, Vann |
| Copyright Year | 1991 |
| Abstract | This report demonstrates that specific proteolysis of brain spectrin by a calcium-dependent protease, calpain I, abolishes association of brain spectrin with the ankyrin-independent binding site(s) in brain membranes. Calpain I cleaves the beta subunit of spectrin at the N-terminal end leaving a 218-kDa fragment and cleaves the alpha subunit in the midregion to produce 150- and 130-kDa fragments. Calpain-proteolyzed spectrin almost completely loses the capacity to displace binding of intact spectrin to membranes. Spectrin digested by calpain I under conditions that almost completely destroyed membrane-binding remained associated as a tetramer and retained about 60% of the ability to associate with actin filaments. Cleavage of spectrin occurred at sites distinct from the membrane-binding site which is located on the beta subunit since the isolated 218-kDa fragment of the beta subunit as well as a reconstituted complex of alpha and 218-kDa beta subunit fragment partially regained binding activity. Moreover, cleavage of the alpha subunit alone reduced the affinity of spectrin for membranes by 2-fold. A consequence of distinct sites for calpain I cleavage and membrane-binding is that calpain I can digest spectrin while spectrin is complexed with other proteins and therefore has the potential to mediate disassembly of a spectrin-actin network from membranes. |
| File Format | PDF HTM / HTML |
| PubMed reference number | 1833394 |
| Journal | Medline |
| Volume Number | 266 |
| Issue Number | 27 |
| Alternate Webpage(s) | http://www.jbc.org/content/266/27/18200.full.pdf |
| Journal | The Journal of biological chemistry |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
