The centrosomal protein RAS association domain family protein 1A (RASSF1A)-binding protein 1 regulates mitotic progression by recruiting RASSF1A to spindle poles.
The protein RAS association domain family protein 1A (RASSF1A), which is encoded by a gene that is frequently silenced in many types of sporadic tumor, functions in mitosis as a regulator of the anaphase-promoting complex (APC). With the use of a yeast two-hybrid screen, we identified a human protein, previously designated C19ORF5, that interacts with RASSF1A. This protein, here redesignated RASSF1A-binding protein 1 (RABP1), contains two microtubule-associated protein domains, and its association with RASSF1A was confirmed in mammalian cells by immunoprecipitation and immunofluorescence analyses. RABP1 was found to be localized to the centrosome throughout the cell cycle in a manner dependent on its microtubule-associated protein domains. Ectopic expression of RABP1 induced both stabilization of mitotic cyclins and mitotic arrest at prometaphase in a RASSF1A-dependent manner. It also increased the extent of association between RASSF1A and Cdc20. Conversely depletion of RABP1 by RNA interference prevented both the localization of RASSF1A to the spindle poles as well as its binding to Cdc20, resulting in premature destruction of mitotic cyclins and acceleration of mitotic progression. These findings indicate that RABP1 is required for the recruitment of RASSF1A to the spindle poles and for its inhibition of APC-Cdc20 activity during mitosis.
Song
Min Sup
MS
Department of Biological Sciences, Biomedical Research Center, Korea Advanced Institute of Science and Technology, 373-1 Guseoung-D, Yuseong-G, Daejeon 305-701, Korea.
Chang
Jin Sook
JS
Song
Su Jeong
SJ
Yang
Tae Hong
TH
Lee
Ho
H
Lim
Dae-Sik
DS
D064173:Anaphase-Promoting Complex-Cyclosome; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism; D018385:Centrosome / Q000378:metabolism*; D016213:Cyclins / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008938:Mitosis / Q000502:physiology*; D011485:Protein Binding; D008941:Spindle Apparatus / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism
D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D016213:Cyclins; C411762:RASSF1 protein, human; D025521:Tumor Suppressor Proteins; C577488:CDC20 protein, human; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome