Clasps are CLIP-115 and -170 associating proteins involved in the regional regulation of microtubule dynamics in motile fibroblasts.
CLIP-170 and CLIP-115 are cytoplasmic linker proteins that associate specifically with the ends of growing microtubules and may act as anti-catastrophe factors. Here, we have isolated two CLIP-associated proteins (CLASPs), which are homologous to the Drosophila Orbit/Mast microtubule-associated protein. CLASPs bind CLIPs and microtubules, colocalize with the CLIPs at microtubule distal ends, and have microtubule-stabilizing effects in transfected cells. After serum induction, CLASPs relocalize to distal segments of microtubules at the leading edge of motile fibroblasts. We provide evidence that this asymmetric CLASP distribution is mediated by PI3-kinase and GSK-3 beta. Antibody injections suggest that CLASP2 is required for the orientation of stabilized microtubules toward the leading edge. We propose that CLASPs are involved in the local regulation of microtubule dynamics in response to positional cues.
Akhmanova
A
A
MGC Department of Cell Biology and Genetics, Erasmus University, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands.
Hoogenraad
C C
CC
Drabek
K
K
Stepanova
T
T
Dortland
B
B
Verkerk
T
T
Vermeulen
W
W
Burgering
B M
BM
De Zeeuw
C I
CI
Grosveld
F
F
Galjart
N
N
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D002645:Chickens; D003001:Cloning, Molecular; D004330:Drosophila; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection
D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; C109878:cytoplasmic linker protein 115; C076744:cytoplasmic linker protein 170