GFP Chimeras of E-MAP-115 (ensconsin) Domains Mimic Behavior of the Endogenous Protein in vitro and in vivo

Cell Structure and Function

J. Chloe Bulinski²  Kathleen Faire¹  Dorota Gruber¹  Winston Chang²  Pallavi Prasad¹ 

[1] Department of Anatomy & Cell Biology and Pathology, Columbia University, College of Physicians & Surgeons, 630 W. 168th St. New York, NY 10032-3702, USA;Integrated Program in Cell, Molecular, & Biophysical Studies, Columbia University, College of Physicians & Surgeons, 630 W. 168th St. New York, NY 10032-3702, USA

关键词: Multimeric GFP;    Taxol;    cytoskeleton;    carcinoma cells;    in vivo microtubule imaging;   

DOI  :  10.1247/csf.24.313

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(21)Cited-By(4)E-MAP-115 (ensconsin) is a microtubule-associated protein (MAP) abundant in carcinoma and other epithelia-derived cells. We expressed chimeras of green fluorescent protein (GFP) conjugated to ensconsin's N-terminal MT-binding domain (EMTB), to study distribution, dynamics, and function of the MAP in living cells. We tested the hypothesis that behavior of expressed GFP-EMTB accurately matched behavior of endogenous ensconsin. Like endogenous MAP, GFP-EMTB was associated with microtubules in living or fixed cells, and microtubule association of either molecule was impervious to extraction with nonionic detergents. In cell lysates both GFP-EMTB and endogenous ensconsin were dissociated from microtubules by identical salt extraction conditions, and both molecules remained bound to a calcium-stable subset of Taxol-stabilized microtubules. These data show that microtubule association of ensconsin was affected neither by the absence of domains other than its microtubule-binding domain, nor by the presence of appended GFP. We took advantage of this finding to generate constructs in which additional GFP moieties were attached to EMTB, to obtain a more intensely fluorescent reporter of in vivo MAP binding. We show here that expression of chimeric proteins consisting of five GFP molecules attached to a single EMTB molecule produces brightly labeled microtubules without compromising the behavior of the MAP or the microtubules to which it is attached. Thus, we have demonstrated the utility of chimeric proteins containing GFP multimers as authentic reporters, of ensconsin distribution and dynamics ; expression of these GFP-EMTB chimeric molecules also provides a non-perturbing label of the microtubule system in living cells.

【 授权许可】

Unknown