• Register
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.


Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.


Centrosomal proteins CG-NAP and kendrin provide microtubule nucleation sites by anchoring gamma-tubulin ring complex.

Microtubule assembly is initiated by the gamma-tubulin ring complex (gamma-TuRC). In yeast, the microtubule is nucleated from gamma-TuRC anchored to the amino-terminus of the spindle pole body component Spc110p, which interacts with calmodulin (Cmd1p) at the carboxy-terminus. However, mammalian protein that anchors gamma-TuRC remains to be elucidated. A giant coiled-coil protein, CG-NAP (centrosome and Golgi localized PKN-associated protein), was localized to the centrosome via the carboxyl-terminal region. This region was found to interact with calmodulin by yeast two-hybrid screening, and it shares high homology with the carboxyl-terminal region of another centrosomal coiled-coil protein, kendrin. The amino-terminal region of either CG-NAP or kendrin indirectly associated with gamma-tubulin through binding with gamma-tubulin complex protein 2 (GCP2) and/or GCP3. Furthermore, endogenous CG-NAP and kendrin were coimmunoprecipitated with each other and with endogenous GCP2 and gamma-tubulin, suggesting that CG-NAP and kendrin form complexes and interact with gamma-TuRC in vivo. These proteins were localized to the center of microtubule asters nucleated from isolated centrosomes. Pretreatment of the centrosomes by antibody to CG-NAP or kendrin moderately inhibited the microtubule nucleation; moreover, the combination of these antibodies resulted in stronger inhibition. These results imply that CG-NAP and kendrin provide sites for microtubule nucleation in the mammalian centrosome by anchoring gamma-TuRC.

Pubmed ID: 12221128


  • Takahashi M
  • Yamagiwa A
  • Nishimura T
  • Mukai H
  • Ono Y


Molecular biology of the cell

Publication Data

September 10, 2002

Associated Grants


Mesh Terms

  • A Kinase Anchor Proteins
  • Adaptor Proteins, Signal Transducing
  • Amino Acid Sequence
  • Animals
  • CHO Cells
  • COS Cells
  • Calmodulin-Binding Proteins
  • Carrier Proteins
  • Cell Line
  • Cell Nucleus
  • Centrosome
  • Cricetinae
  • Cytoskeletal Proteins
  • DNA, Complementary
  • HeLa Cells
  • Humans
  • Immunoblotting
  • Microscopy, Fluorescence
  • Microtubule-Associated Proteins
  • Microtubules
  • Models, Genetic
  • Molecular Sequence Data
  • Precipitin Tests
  • Protein Binding
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Transfection
  • Tubulin
  • Two-Hybrid System Techniques