Microtubule-bundling activity of APC is stimulated by interaction with PSD-95.
Adenomatous polyposis coli (APC) tumor suppressor protein binds to microtubules, leading to microtubule bundling and stabilization. The protein also interacts with postsynaptic density (PSD)-95, a major scaffolding protein in neurons. Here, we analyzed the effects of PSD-95 on the microtubule-bundling activity of APC. The coexpression of APC and PSD-95 in COS-7 cells enhanced microtubule-bundle formation compared with the expression of APC alone. A mutant APC variant that does not associate with PSD-95 did not enhance microtubule bundling, despite coexpression with PSD-95. Immunoelectron microscopy showed that the APC-PSD-95 complex sometimes colocalized on microtubules in processes of cultured neurons. These results suggest that the microtubule-bundling activity of APC is regulated by its interaction with PSD-95, which might modulate microtubule architecture and dynamics in neurons.
Takamori
Nobutake
N
Department of Anatomy I, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
Shimomura
Atsushi
A
Senda
Takao
T
D025601:Adenomatous Polyposis Coli Protein / Q000502:physiology*; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008870:Microtubules / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000502:physiology*
D025601:Adenomatous Polyposis Coli Protein; D009419:Nerve Tissue Proteins; C033652:postsynaptic density proteins