The dynamic behavior of the APC-binding protein EB1 on the distal ends of microtubules.

Abstract

Adenomatous polyposis coli protein (APC) is a well-characterized tumor suppressor protein [1] [2] [3]. 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 [4]. EB1, which was identified as an APC-binding protein by yeast two-hybrid analysis [5], was also reported to be associated with microtubules [6] [7] [8]. 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.

• Authors: Y Mimori-Kiyosue, N Shiina, S Tsukita
• Journal: Current biology : CB (Curr Biol) Vol. 10 Issue 14 Pg. 865-8 (Jul 13 2000) ISSN: 0960-9822 [Print] England
• PMID: 10899006 (Publication Type: Journal Article)

Chemical References

• Adenomatous Polyposis Coli Protein
• Cytoskeletal Proteins
• EB1 microtubule binding proteins
• Luminescent Proteins
• Microtubule-Associated Proteins
• Recombinant Fusion Proteins
• Green Fluorescent Proteins

Topics

• Adenomatous Polyposis Coli Protein
• Animals
• Cell Line
• Cytoskeletal Proteins (genetics, metabolism)
• Genes, APC
• Green Fluorescent Proteins
• Humans
• Luminescent Proteins (genetics, metabolism)
• Microtubule-Associated Proteins (genetics, metabolism)
• Microtubules (metabolism)
• Recombinant Fusion Proteins (genetics, metabolism)
• Transfection
• Xenopus