Transient expression of fluorescent tau proteins promotes process formation in PC12 cells: contributions of the tau C-terminus to this process.
The neuronal microtubule-associated protein tau promotes microtubule assembly and has been implicated in the development of axonal morphology. In this study, PC12 cells were transiently transfected with constructs coding fusion proteins of human tau with green fluorescent protein (GFP). Expression of tau constructs actively stabilized microtubules. Expression of the C-terminus of tau can mimic this effect in living cells, though to a lesser extent because of the absence of the tau N-terminus. However, tau colocalization with microtubules did not require the presence of the tau N-terminus. Transient expression of tau (including tau24, a four-repeat human tau isoform encoded in 383 residues, and tau23, human fetal tau isoform encoded in 352 residues) stimulated process formation in PC12 cells, and this occurred faster with tau24 than with tau23. The residues (residues 154-172 in tau23) that confer microtubule nucleation activity of tau in vitro are not required for tau-directed process formation. However, when tau induces the formation of cellular processes in response to cortical breakdown by cytochalasin B, residues 154-172 must be present. Thus, it appears that tau may serve to promote cellular process outgrowth in cultured neuronal cells and that C-terminus of tau is essential to this process.
Yu
Jiang-Zhou
JZ
Department of Physiology and Biophysics, University of Illinois at Chicago College of Medicine, Chicago, Illinois 60612-7342, USA.
Kuret
Jeff
J
Rasenick
Mark M
MM
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D048429:Cell Size / Q000187:drug effects / Q000235:genetics; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D003571:Cytochalasin B / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D005822:Genetic Vectors / Q000502:physiology; D049452:Green Fluorescent Proteins; D020439:Growth Cones / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D008164:Luminescent Proteins / Q000235:genetics; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D016716:PC12 Cells; D020033:Protein Isoforms / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000187:drug effects / Q000502:physiology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics; D016875:tau Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism
D008164:Luminescent Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D016875:tau Proteins; D049452:Green Fluorescent Proteins; D003571:Cytochalasin B