The Calmodulin-binding Domain from a Plant Kinesin Functions as a Modular Domain in Conferring Ca2+-Calmodulin Regulation to Animal Plus- and Minus-end Kinesins
Plant kinesin-like calmodulin-binding protein (KCBP) is a novel member of the kinesin superfamily that interacts with calmodulin (CaM) via its CaM-binding domain (CBD). Activated CaM (Ca 2+ -CaM) has been shown to inhibit KCBP interaction with microtubules (MTs) thereby abolishing its motor- and MT-...
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Published in | The Journal of biological chemistry Vol. 277; no. 50; pp. 48058 - 48065 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
American Society for Biochemistry and Molecular Biology
13.12.2002
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Subjects | |
Online Access | Get full text |
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Summary: | Plant kinesin-like calmodulin-binding protein (KCBP) is a novel member of the kinesin superfamily that interacts with calmodulin
(CaM) via its CaM-binding domain (CBD). Activated CaM (Ca 2+ -CaM) has been shown to inhibit KCBP interaction with microtubules (MTs) thereby abolishing its motor- and MT-dependent ATPase
activities. To test whether the fusion of CBD to non-CaM-binding kinesins confers Ca 2+ -CaM regulation, we fused the CBD of KCBP to the N or C terminus of a minus-end (non-claret disjunction) or C terminus of
a plus-end ( Drosophila kinesin) motor. Purified chimeric kinesins bound CaM in a Ca 2+ -dependent manner whereas non-claret disjunction, Drosophila kinesin, and KCBP that lack a CBD did not. As in the case of KCBP with CBD, the interaction of chimeric motors with MTs,
as well as their MT-stimulated ATPase activity, was inhibited by Ca 2+ -CaM. The presence of a spacer between the motor and CBD did not alter Ca 2+ -CaM regulation. However, KCBP interaction with MTs and its MT-stimulated ATPase activity were not inhibited when the motor
domain and CBD were added separately, suggesting that Ca 2+ -CaM regulation of CaM-binding motors occurs only when the CBD is attached to the motor domain. These results show that the
fusion of the CBD to animal motors confers Ca 2+ -CaM regulation and suggest that the CBD functions as a modular domain in disrupting motor-MT interaction. Our data also support
the hypothesis that CaM-binding kinesins may have evolved by addition of a CBD to a kinesin motor domain. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.M205459200 |