CLASP1 and CLASP2 bind to EB1 and regulate microtubule plus-end dynamics at the cell cortex.
CLIP-associating protein (CLASP) 1 and CLASP2 are mammalian microtubule (MT) plus-end binding proteins, which associate with CLIP-170 and CLIP-115. Using RNA interference in HeLa cells, we show that the two CLASPs play redundant roles in regulating the density, length distribution and stability of interphase MTs. In HeLa cells, both CLASPs concentrate on the distal MT ends in a narrow region at the cell margin. CLASPs stabilize MTs by promoting pauses and restricting MT growth and shortening episodes to this peripheral cell region. We demonstrate that the middle part of CLASPs binds directly to EB1 and to MTs. Furthermore, we show that the association of CLASP2 with the cell cortex is MT independent and relies on its COOH-terminal domain. Both EB1- and cortex-binding domains of CLASP are required to promote MT stability. We propose that CLASPs can mediate interactions between MT plus ends and the cell cortex and act as local rescue factors, possibly through forming a complex with EB1 at MT tips.
Mimori-Kiyosue
Yuko
Y
KAN Research Institute, Kyoto Research Park, Shimogyo-ku, Kyoto 600-8815, Japan.
Grigoriev
Ilya
I
Lansbergen
Gideon
G
Sasaki
Hiroyuki
H
Matsui
Chiyuki
C
Severin
Fedor
F
Galjart
Niels
N
Grosveld
Frank
F
Vorobjev
Ivan
I
Tsukita
Shoichiro
S
Akhmanova
Anna
A
D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003599:Cytoskeleton / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014404:Tubulin / Q000235:genetics / Q000378:metabolism
C497850:CLASP1 protein, human; C497851:CLASP2 protein, human; C405804:EB1 microtubule binding proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D014404:Tubulin; C109878:cytoplasmic linker protein 115; C076744:cytoplasmic linker protein 170