Regulation of a heterodimeric kinesin-2 through an unprocessive motor domain that is turned processive by its partner.
Cilia are microtubule-based protrusions of the plasma membrane found on most eukaryotic cells. Their assembly is mediated through the conserved intraflagellar transport mechanism. One class of motor proteins involved in intraflagellar transport, kinesin-2, is unique among kinesin motors in that some of its members are composed of two distinct polypeptides. However, the biological reason for heterodimerization has remained elusive. Here we provide several interdependent reasons for the heterodimerization of the kinesin-2 motor KLP11/KLP20 of Caenorhabditis elegans cilia. One motor domain is unprocessive as a homodimer, but heterodimerization with a processive partner generates processivity. The "unprocessive" subunit is kept in this partnership as it mediates an asymmetric autoregulation of the motor activity. Finally, heterodimerization is necessary to bind KAP1, the in vivo link between motor and cargo.
Brunnbauer
Melanie
M
Physik Department E22, Technische Universität München, James-Franck-Strasse, D-85748 Garching, Germany.
Mueller-Planitz
Felix
F
Kösem
Süleyman
S
Ho
Thi Hieu
TH
Dombi
Renate
R
Gebhardt
J Christof M
JC
Rief
Matthias
M
Okten
Zeynep
Z
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000378:metabolism*; D002923:Cilia / Q000378:metabolism; D016547:Kinesins / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D009068:Movement; D055503:Protein Multimerization; D016415:Sequence Alignment
D029742:Caenorhabditis elegans Proteins; D016547:Kinesins