東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Examining kinesin motor family diver...

Endres, Nicholas F.

Linked to FindBook

Google Book

Amazon

博客來

Examining kinesin motor family diversity: A mechanistic study of Ncd and OSM-3 motor proteins.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Examining kinesin motor family diversity: A mechanistic study of Ncd and OSM-3 motor proteins./
Author:	Endres, Nicholas F.
Description:	78 p.
Notes:	Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2414.
Contained By:	Dissertation Abstracts International67-05B.
Subject:	Biology, Cell. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3221156
ISBN:	9780542708701

Examining kinesin motor family diversity: A mechanistic study of Ncd and OSM-3 motor proteins.
Endres, Nicholas F.

Examining kinesin motor family diversity: A mechanistic study of Ncd and OSM-3 motor proteins. - 78 p.

Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2414.

Thesis (Ph.D.)--University of California, San Francisco, 2006.

Kinesin motor proteins produce motion and force along microtubules and are essential for the organization of subcellular components (Vale, 2003). The kinesin superfamily is divided into 14 subfamilies that carry out a variety of biological functions (Miki et al., 2005). In spite of their diversity, Kinesin motors all share a conserved catalytic domain that binds to microtubule and hydrolyzes ATP (Vale and Milligan, 2000). The two studies presented here are examples of how kinesin motors can be uniquely adapted to perform their specific cellular functions. The first study focuses on the Kinesin-14 family member Ncd. Most kinesin motors, exemplified by Kinesin-1, move towards the microtubule plus end, and the structural changes that govern this directional preference have been described (Rice et al., 1999). In contrast, the structural changes underlying the minus-end-directed motility of Kinesin-14 motors are less well understood. Using cryo-electron microscopy, we demonstrate that a coiled-coil mechanical element of microtubule-bound Ncd rotates &sim;70° towards the minus end upon ATP binding. Extending or shortening this coiled coil increases or decreases velocity, respectively, without affecting ATPase activity. Our results show that the force-producing conformational change in Ncd occurs on ATP binding, as in other kinesins, but involves the swing of a lever-arm mechanical element similar to that described for myosins. The second study focuses on OSM-3, a Kinesin-2 family member involved in intraflagellar transport (IFT) (Scholey et al., 2004). Here, using a single molecule fluorescence assay, we show that bacterially-expressed OSM-3 GFP does not move processively (multiple steps along a microtubule without dissociation). However, a single point mutation in a predicted hinge region of the OSM-3 coiled-coil stalk, as well as a deletion of that hinge, activates robust processive movement of OSM-3. The processivity of wild-type OSM-3 also can be activated by attaching the motor to beads in an optical trap. Sucrose gradient analysis reveals that OSM-3 adopts a compact conformation that becomes extended in the hinge mutants or at high salt. We propose that the processivity of OSM-3 is repressed by an intramolecular interaction in vivo that can be relieved by IFT cargo binding.

ISBN: 9780542708701Subjects--Topical Terms:

1017686
Biology, Cell.

Examining kinesin motor family diversity: A mechanistic study of Ncd and OSM-3 motor proteins.
LDR:03238nmm 2200277 4500 001 1832060
005 20070628102650.5
008 130610s2006 eng d
020 $a 9780542708701
035 $a (UnM)AAI3221156
035 $a AAI3221156
040 $a UnM $c UnM
100 1 $a Endres, Nicholas F. $3 1920813
245 1 0 $a Examining kinesin motor family diversity: A mechanistic study of Ncd and OSM-3 motor proteins.
300 $a 78 p.
500 $a Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2414.
500 $a Adviser: Ronald D. Vale.
502 $a Thesis (Ph.D.)--University of California, San Francisco, 2006.
520 $a Kinesin motor proteins produce motion and force along microtubules and are essential for the organization of subcellular components (Vale, 2003). The kinesin superfamily is divided into 14 subfamilies that carry out a variety of biological functions (Miki et al., 2005). In spite of their diversity, Kinesin motors all share a conserved catalytic domain that binds to microtubule and hydrolyzes ATP (Vale and Milligan, 2000). The two studies presented here are examples of how kinesin motors can be uniquely adapted to perform their specific cellular functions. The first study focuses on the Kinesin-14 family member Ncd. Most kinesin motors, exemplified by Kinesin-1, move towards the microtubule plus end, and the structural changes that govern this directional preference have been described (Rice et al., 1999). In contrast, the structural changes underlying the minus-end-directed motility of Kinesin-14 motors are less well understood. Using cryo-electron microscopy, we demonstrate that a coiled-coil mechanical element of microtubule-bound Ncd rotates &sim;70° towards the minus end upon ATP binding. Extending or shortening this coiled coil increases or decreases velocity, respectively, without affecting ATPase activity. Our results show that the force-producing conformational change in Ncd occurs on ATP binding, as in other kinesins, but involves the swing of a lever-arm mechanical element similar to that described for myosins. The second study focuses on OSM-3, a Kinesin-2 family member involved in intraflagellar transport (IFT) (Scholey et al., 2004). Here, using a single molecule fluorescence assay, we show that bacterially-expressed OSM-3 GFP does not move processively (multiple steps along a microtubule without dissociation). However, a single point mutation in a predicted hinge region of the OSM-3 coiled-coil stalk, as well as a deletion of that hinge, activates robust processive movement of OSM-3. The processivity of wild-type OSM-3 also can be activated by attaching the motor to beads in an optical trap. Sucrose gradient analysis reveals that OSM-3 adopts a compact conformation that becomes extended in the hinge mutants or at high salt. We propose that the processivity of OSM-3 is repressed by an intramolecular interaction in vivo that can be relieved by IFT cargo binding.
590 $a School code: 0034.
650 4 $a Biology, Cell. $3 1017686
650 4 $a Biophysics, General. $3 1019105
690 $a 0379
690 $a 0786
710 2 0 $a University of California, San Francisco. $3 1025118
773 0 $t Dissertation Abstracts International $g 67-05B.
790 1 0 $a Vale, Ronald D., $e advisor
790 $a 0034
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3221156