GFAP isoforms control intermediate filament network dynamics, cell morphology, and focal adhesions

TY - JOUR

T1 - GFAP isoforms control intermediate filament network dynamics, cell morphology, and focal adhesions

AU - Moeton, Martina

AU - Stassen, Oscar M J A

AU - Sluijs, Jacqueline A

AU - van der Meer, Vincent W N

AU - Kluivers, Liselot J

AU - van Hoorn, Hedde

AU - Schmidt, Thomas

AU - Reits, Eric A J

AU - van Strien, Miriam E

AU - Hol, Elly M

PY - 2016

Y1 - 2016

N2 - Glial fibrillary acidic protein (GFAP) is the characteristic intermediate filament (IF) protein in astrocytes. Expression of its main isoforms, GFAPα and GFAPδ, varies in astrocytes and astrocytoma implying a potential regulatory role in astrocyte physiology and pathology. An IF-network is a dynamic structure and has been functionally linked to cell motility, proliferation, and morphology. There is a constant exchange of IF-proteins with the network. To study differences in the dynamic properties of GFAPα and GFAPδ, we performed fluorescence recovery after photobleaching experiments on astrocytoma cells with fluorescently tagged GFAPs. Here, we show for the first time that the exchange of GFP-GFAPδ was significantly slower than the exchange of GFP-GFAPα with the IF-network. Furthermore, a collapsed IF-network, induced by GFAPδ expression, led to a further decrease in fluorescence recovery of both GFP-GFAPα and GFP-GFAPδ. This altered IF-network also changed cell morphology and the focal adhesion size, but did not alter cell migration or proliferation. Our study provides further insight into the modulation of the dynamic properties and functional consequences of the IF-network composition.

AB - Glial fibrillary acidic protein (GFAP) is the characteristic intermediate filament (IF) protein in astrocytes. Expression of its main isoforms, GFAPα and GFAPδ, varies in astrocytes and astrocytoma implying a potential regulatory role in astrocyte physiology and pathology. An IF-network is a dynamic structure and has been functionally linked to cell motility, proliferation, and morphology. There is a constant exchange of IF-proteins with the network. To study differences in the dynamic properties of GFAPα and GFAPδ, we performed fluorescence recovery after photobleaching experiments on astrocytoma cells with fluorescently tagged GFAPs. Here, we show for the first time that the exchange of GFP-GFAPδ was significantly slower than the exchange of GFP-GFAPα with the IF-network. Furthermore, a collapsed IF-network, induced by GFAPδ expression, led to a further decrease in fluorescence recovery of both GFP-GFAPα and GFP-GFAPδ. This altered IF-network also changed cell morphology and the focal adhesion size, but did not alter cell migration or proliferation. Our study provides further insight into the modulation of the dynamic properties and functional consequences of the IF-network composition.

U2 - 10.1007/s00018-016-2239-5

DO - 10.1007/s00018-016-2239-5

M3 - Article

C2 - 27141937

SN - 1420-682X

VL - 73

SP - 4101

EP - 4120

JO - Cellular and Molecular Life Sciences

JF - Cellular and Molecular Life Sciences

ER -