| First Author | Iwaya N | Year | 2012 |
| Journal | FEBS J | Volume | 279 |
| Issue | 7 | Pages | 1339-52 |
| PubMed ID | 22325007 | Mgi Jnum | J:195104 |
| Mgi Id | MGI:5476424 | Doi | 10.1111/j.1742-4658.2012.08528.x |
| Citation | Iwaya N, et al. (2012) Effect of Ca2+ on the microtubule-severing enzyme p60-katanin. Insight into the substrate-dependent activation mechanism. FEBS J 279(7):1339-52 |
| abstractText | Katanin p60 (p60-katanin) is a microtubule (MT)-severing enzyme and its activity is regulated by the p80 subunit (adaptor-p80). p60-katanin consists of an N-terminal domain, followed by a single ATPase associated with various cellular activities (AAA) domain. We have previously shown that the N-terminal domain serves as the binding site for MT, the substrate of p60-katanin. In this study, we show that the same domain shares another interface with the C-terminal domain of adaptor-p80. We further show that Ca(2+) ions inhibit the MT-severing activity of p60-katanin, whereas the MT-binding activity is preserved in the presence of Ca(2+). In detail, the basal ATPase activity of p60-katanin is stimulated twofold by both MTs and the C-terminal domain of adaptor-p80, whereas Ca(2+) reduces elevated ATPase activity to the basal level. We identify the Ca(2+) -binding site at the end of helix 2 of the N-terminal domain, which is different from the MT-binding interface. On the basis of these observations, we propose a speculative model in which spatial rearrangement of the N-terminal domain relative to the C-terminal AAA domain may be important for productive ATP hydrolysis towards MT-severing. Our model can explain how Ca(2+) regulates both severing and ATP hydrolysis activity, because the Ca(2+) -binding site on the N-terminal domain moves close to the AAA domain during MT severing. |
