XB-ART-10679Curr Biol July 13, 2000; 10 (14): 865-8.
Adenomatous polyposis coli protein (APC) is a well-characterized tumor suppressor protein   . We previously showed that APC tagged with green fluorescent protein (GFP) in Xenopus A6 epithelial cells moves along a subset of microtubules and accumulates at their growing plus ends in cell extensions . EB1, which was identified as an APC-binding protein by yeast two-hybrid analysis , was also reported to be associated with microtubules   . To examine the interaction between APC and EB1 within cells, we compared the dynamic behavior of EB1-GFP with that of APC-GFP in A6 transfectants. Time-lapse microscopy of live cells at interphase revealed that EB1-GFP was concentrated at all of the growing microtubule ends throughout the cytoplasm and abruptly disappeared from the ends when microtubules began to shorten. Therefore, EB1 appeared to be co-localized and interact with APC on the growing ends of a subset of microtubules. When APC-GFP was overexpressed, endogenous EB1 was recruited to APC-GFP, which accumulated in large amounts on microtubules. On the other hand, when microtubules were disassembled by nocodazole, EB1 was not co-localized with APC-GFP, which was concentrated along the basal plasma membrane. During mitosis, APC appeared to be dissociated from microtubules, whereas EB1-GFP continued to concentrate at microtubule growing ends. These findings showed that the APC-EB1 interaction is regulated within cells and is allowed near the ends of microtubules only under restricted conditions.
PubMed ID: 10899006
Article link: Curr Biol
Species referenced: Xenopus laevis
Genes referenced: cox7a2l mapre1