Conformational changes in CLIP-170 regulate its binding to microtubules and dynactin localization.
Cytoplasmic linker protein (CLIP)-170, CLIP-115, and the dynactin subunit p150(Glued) are structurally related proteins, which associate specifically with the ends of growing microtubules (MTs). Here, we show that down-regulation of CLIP-170 by RNA interference results in a strongly reduced accumulation of dynactin at the MT tips. The NH(2) terminus of p150(Glued) binds directly to the COOH terminus of CLIP-170 through its second metal-binding motif. p150(Glued) and LIS1, a dynein-associating protein, compete for the interaction with the CLIP-170 COOH terminus, suggesting that LIS1 can act to release dynactin from the MT tips. We also show that the NH(2)-terminal part of CLIP-170 itself associates with the CLIP-170 COOH terminus through its first metal-binding motif. By using scanning force microscopy and fluorescence resonance energy transfer-based experiments we provide evidence for an intramolecular interaction between the NH(2) and COOH termini of CLIP-170. This interaction interferes with the binding of the CLIP-170 to MTs. We propose that conformational changes in CLIP-170 are important for binding to dynactin, LIS1, and the MT tips.
Lansbergen
Gideon
G
MGC Dept. of Cell Biology and of Genetics, Erasmus Medical Center, P.O. Box 1738, 3000 DR Rotterdam, Netherlands.
Komarova
Yulia
Y
Modesti
Mauro
M
Wyman
Claire
C
Hoogenraad
Casper C
CC
Goodson
Holly V
HV
Lemaitre
Régis P
RP
Drechsel
David N
DN
van Munster
Erik
E
Gadella
Theodorus W J
TW
Grosveld
Frank
F
Galjart
Niels
N
Borisy
Gary G
GG
Akhmanova
Anna
A
D020816:Amino Acid Motifs / Q000235:genetics; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D019556:COS Cells; D015536:Down-Regulation / Q000235:genetics; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins / Q000235:genetics* / Q000378:metabolism*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D009363:Neoplasm Proteins; D011485:Protein Binding / Q000235:genetics; D011487:Protein Conformation; D017434:Protein Structure, Tertiary / Q000235:genetics; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference
D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D021122:Protein Subunits; C076744:cytoplasmic linker protein 170