A guide to selecting high-performing renewable antibodies for KIF5A (Q12840) across western blot, immunoprecipitation, and immunofluorescence

Introduction

KIF5A is a member of the KIF5 family of kinesin motor proteins that mediates anterograde transport along microtubules. In neurons, it plays a critical role in the transport of mitochondria and synaptic vesicles from the soma to the synapse, supporting axonal maintenance and function.¹ Mutations in the KIF5A gene impair cargo transport and are associated with amyotrophic lateral sclerosis (ALS).²

Here, we characterized ten antibodies against KIF5A, for use in western blot, immunoprecipitation, and immunofluorescence using standardized protocols. Antibody performance was assessed by comparing signal in wild-type (WT) and knockout (KO) cell lines. The resulting data can guide the selection of antibodies best suited to specific research needs, enabling robust biochemical and cellular assessment of the target.

This work is part of a broader collaborative initiative involving academics, funders, and antibody manufacturers, aimed at improving biomedical research reproducibility through the systematic characterization of commercial antibodies against human proteins and open data sharing. Antibodies are provided in-kind by participating manufacturers. The approach involves identifying cell lines with sufficient target expression, generating or sourcing corresponding KO cell lines, and evaluating commercially available antibodies, with a focus on renewable (monoclonal and recombinant) reagents.³ We do not provide explicit antibody recommendations; rather, the data are presented to enable independent interpretation. Guidance on data interpretation is available via the YCharOS gateway⁴ and in Table 4 of this data note.

Table 4. Illustrations to assess antibody performance in all western blot, immunoprecipitation and immunofluorescence.

Western blot	Immunoprecipitation	Immunofluorescence

Results and discussion

Our standard protocol involves comparing readouts from WT and KO cells.³ The first step is to identify a cell line expressing sufficient levels of the target protein to generate a measurable signal with antibodies. To this end, we examined the DepMap transcriptomics database (Cancer Dependency Map Portal, RRID:SCR_017655) to identify cell lines with expression levels greater than 2.5 log2 (transcripts per million “TPM” + 1), a threshold we have found to be suitable.⁵ The U-87 MG cell line expresses the KIF5A transcript at 4.1 log₂ TPM + 1, and a corresponding U-87 MG KIF5A KO cell line was obtained from Abcam ( Table 1). Moreover, as seen on DepMap, the U-87 MG does not carry mutations in KIF5A that could affect antibody-epitope binding.

First, all ten antibodies were tested in western blot. WT and KIF5A KO protein lysates were resolved on SDS-PAGE, transferred to nitrocellulose membranes, and probed in parallel with KIF5A antibodies in parallel ( Figure 1).

Figure 1. KIF5A antibody screening by western blot.

Lysates of U-87 MG WT and KIF5A KO were prepared, and 60 μg of protein were processed for western blot with the indicated KIF5A antibodies. The Ponceau stained transfers of each blot are presented to show equal loading of WT and KO lysates and protein transfer efficiency from the acrylamide gels to the nitrocellulose membrane. Antibody dilutions were chosen according to the recommendations of the antibody supplier. Antibody dilutions used: ab322900** at 1/1000, ab5628 at 1/500, ARP33868_P050 at 1/500, 92872** at 1/500, GTX104875 at 1/500, GTX113761 at 1/500, 21186–1-AP at 1/500, 67009–1-Ig* at 1/500, 84013–4-RR** at 1/3000, 84013–5-RR** at 1/1000. Predicted band size: 117.3 kDa. ** = recombinant antibody, * = monoclonal antibody.

The ability of antibodies to capture KIF5A from U-87 MG lysates was assessed by immunoprecipitation, followed by western blot analysis. Equal amounts of the starting material (SM) and the unbound fractions (UB), as well as the whole immunoprecipitate (IP) eluates were separated by SDS-PAGE. For detection, 92872**, a specific KIF5A antibody identified in Figure 1 was used ( Figure 2).

Figure 2. KIF5A antibody screening by immunoprecipitation.

U-87 MG lysates were prepared, and immunoprecipitation was performed for 2 h using 3.0 mg of lysate and 2.0 μg of the indicated KIF5A antibodies pre-coupled to Dynabeads protein A or protein G. Samples were washed and processed for western blot with the KIF5A antibody 92872** used at 1/500. The Ponceau stained transfers of each blot are shown. SM = 2% starting material; UB = 2% unbound fraction; IP = immunoprecipitate. ** = recombinant antibody, * = monoclonal antibody.

For immunofluorescence, antibodies were screened using a mosaic strategy. WT and KIF5A KO cells were pre-labelled with distinct fluorescent dyes to enable discrimination between the two populations and imaged within the same field of view, thereby reducing staining, imaging, and analysis biais ( Figure 3). Quantification of immunofluorescence intensity across hundreds of WT and KO cells was performed for each antibody tested,¹ and representative images are shown in Figure 3.

Figure 3. KIF5A antibody screening by immunofluorescence.

U-87 MG WT and KIF5A KO cells were labelled with a green or a far-red fluorescent dye, respectively. WT and KO cells were mixed and plated to a 1:1 ratio in a 96-well plate with optically clear flat-bottom. Culture medium was removed, and cells were fixed with 4% PFA for 15 min at room temperature. Cells were permeabilized with 0.1% Triton-X100 for 10 min at room temperature and stained with the indicated KIF5A antibodies followed by the corresponding Fluor 555 coupled secondary antibody then with DAPI. Acquisition of the blue (nucleus-DAPI), green (WT), red (antibody staining) and far-red (KO) channels was performed. Representative images of the blue and red (grayscale) channels are shown. WT and KO cells are outlined with green and magenta dashed line, respectively. When an antibody was recommended for immunofluorescence by the supplier, we tested it at the recommended dilution and at 1 or 2 μg/ml. The rest of the antibodies were tested at 1 and 2 μg/ml, and the final concentration was selected based on the detection range of the microscope used and a quantitative analysis not shown here. Antibody dilutions used: ab322900** at 1/500, ab5628 at 1/1000, ARP33868_P050 at 1/250, 92872** at 1/1000, GTX104875 at 1/1000, GTX113761 at 1/200, 21186–1-AP at 1/200, 67009–1-Ig* at 1/1000, 84013–4-RR** at 1/250, 84013–5-RR** at 1/400. Bars = 10 μm. ** = recombinant antibody, * = monoclonal antibody.

In summary, we screened ten commercially available KIF5A antibodies in western blot, immunoprecipitation, and immunofluorescence by comparing the signal in WT and KIF5A KO cells. To assist with data interpretation, Table 4 outlines common antibody performance scenarios across applications. High-quality and renewable antibodies detecting KIF5A were identified for each application. Researchers studying KIF5A in other species are encouraged to consider these results and verify predicted species reactivity with the manufacturer before proceeding.

Limitations

Inherent limitations are associated with the antibody characterization platform used in this study. First, the YCharOS project focuses on renewable (recombinant and monoclonal) antibodies and does not test all available antibodies against any given targets. While YCharOS partners provide access to the majority of renewable antibodies, some widely used polyclonal antibodies may not be included.

Second, the YCharOS approach is protein-agnostic and aims to provide objective data on antibody performance without predefined expectations regarding molecular weight or localization. As such, only a brief overview of the protein target is provided, and expert interpretation of banding patterns and subcellular localization is encouraged.

Third, experiments are not performed in biological replicates due to the parallel testing of multiple antibodies recognizing distinct epitopes. The identification of at least one specific antibody supports target expression in WT cells and its absence in KO cells, providing a reference for evaluating other antibodies. Experiments are performed using standardized conditions and master mixes to minimize variability. In immunofluorescence, testing at multiple antibody concentrations provides an additional assessment of specificity. Experiments may be repeated when no signal is detected. Furthermore, these data are generated independently of manufacturers’ validation processes, effectively constituting an external replication.

Finally, conclusions are limited to the experimental conditions and cell line used. The reliance on a single cell type represents a constraint, as protein expression levels can influence antibody performance. The use of cancer cell lines also introduces potential confounders, including mutations that may affect antibody-epitope binding. These limitations are inherent to cell line-based validation approaches.

Method

The standardized protocols used for this antibody characterization study were established and approved by a collaborative group of academics, industry researchers, and antibody manufacturers.³ Brief descriptions of the experimental procedures used in this study are described below.