14-3-3gamma affects dynamics and integrity of glial filaments by binding to phosphorylated GFAP.
Recent findings indicated a protective role of GFAP in ischemic brain, injured spinal cord, and in neurodegenerative disease. We previously demonstrated that 14-3-3gamma, once thought to be neuronal specific, was up-regulated by ischemia in astrocytes and may play a specific protective role in astrocytes. Here we report that 14-3-3gamma associates with both soluble and filamentous GFAP in a phosphorylation- and cell-cycle-dependent manner in primary cultured astrocytes. The amount of association increases during G2/M phase due to more phosphorylated GFAP. Moreover, this interaction is independent of vimentin, another type III intermediate filament protein in astrocytes which forms glial filaments with GFAP. A series of domain deletion mutants and substitution mutations at phosphorylation sites (from serine to alanine) on GFAP demonstrated that serine 8 in the head domain is essential for the direct association of GFAP to 14-3-3gamma. Overexpression of 14-3-3gamma destroyed the integrity and affected the movement of GFAP intermediate filaments. This data demonstrates that 14-3-3gamma contributes to the regulation of dynamics of GFAP filaments, which may contribute to the stability of the cytoskeleton and the mechanisms of central nervous system neurodegenerative disease.
Li
Huihui
H
The Key Laboratory of Cell Proliferation and Differentiation of Ministry of Education and The State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Peking University, Beijing 100871, China.
Guo
Yan
Y
Teng
Junlin
J
Ding
Mingxiao
M
Yu
Albert Cheung Hoi
AC
Chen
Jianguo
J
D048948:14-3-3 Proteins / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D002478:Cells, Cultured; D036681:Fluorescence Recovery After Photobleaching; D031541:Fluorescence Resonance Energy Transfer; D005455:Fluorescent Antibody Technique; D016195:G2 Phase / Q000502:physiology; D020869:Gene Expression Profiling; D015723:Gene Library; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D007511:Ischemia / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014746:Vimentin / Q000378:metabolism
D048948:14-3-3 Proteins; D005904:Glial Fibrillary Acidic Protein; D034741:RNA, Small Interfering; D014746:Vimentin