Intermediate filaments are a diverse group of proteins that grant structure and function to the cytoskeleton. At about 10 nm in diameter, they are intermediate between the diameters of actin filaments and microtubules, the two other major components of the cytoskeleton. Similar to actin, intermediate filaments maintain cell shape by giving rigidity and bearing tension. Intermediate filaments assist in organizing the internal three-dimensional structure of the cell, anchoring organelles and the nucleus in place, and helping form some cell–cell and cell–matrix junctions. Intermediate filaments are not directly involved in cell movement, and because they are plentiful in cells subjected to mechanical stress, their primary role appears to be strengthening cells and tissues. Intermediate filaments are also structural parts of the nuclear lamina that lines the inside of the nuclear membrane and directs the shape of the nucleus. The six major types of intermediate filaments are distinguished and expressed in various cell types.

Intermediate filament marker antibodies can aid in the study of intermediate filament structure and function. Intermediate Filament marker antibodies can also help elucidate the role or roles a protein may play in a number of tasks that are centered in or influenced by intermediate filaments. Invitrogen intermediate filament antibodies are designed to dependably detect the key intermediate filament targets. Each antibody is validated for use in various applications. Key intermediate filament targets include:


Immunohistochemistry detection of nestin on human tonsil tissue

Immunohistochemistry of nestin on human tonsil tissue. To expose target protein, antigen was retrieved using 10 mM sodium citrate followed by microwave treatment for 8–15 minutes. Endogenous peroxidases were blocked in 3% H2O2-methanol for 15 minutes and tissues were blocked in 3% BSA-PBS for 30 minutes at room temperature. Cells were probed with a nestin rabbit polyclonal antibody (Cat. No. MA1-110) at a dilution of 1:100 overnight in a humidified chamber. Tissues were washed in PBST and detection was performed using a secondary antibody conjugated to HRP. DAB staining buffer was applied and tissues were counterstained with hematoxylin and prepped for mounting. Images were taken at 40x magnification.

Immunofluorescent analysis of GFAP

Immunofluorescent analysis of GFAP in human iPSC-derived astrocytes. The cells were fixed with 4% paraformaldehyde for 15 min at room temperature, and then permeabilized and blocked with 0.25% Triton X-100 and 10% donkey serum in PBS for 20 min. Samples were then incubated with a Mouse GFAP monoclonal antibody (green; Cat. No. MA5-12023) at a dilution of 1:500 in PBS containing 0.25% Triton X-100 and 10% donkey serum at 48304C overnight, followed by incubation with Donkey anti-Mouse Alexa Fluor 488 (Cat. No. R37114) at a dilution of 1:1000 as well as DAPI (blue; 1:25000) in PBS containing 0.25% Triton X-100 and 10% donkey serum at room temperature for 1 hour. Images were taken at 40X magnification.