Real lab failures, root causes, and fixes — curated and bilingually annotated by our team.
No signal detected in co-immunoprecipitation experiment. Target protein appears absent despite expected expression.
Phospho-specific antibody shows no or weak signal in IP experiment, while total protein antibody works. Basal phosphorylation levels appear insufficient for detection.
No IP signal despite confirmed protein expression in input control. Antibody works in western blot of denatured lysate but fails in native IP conditions.
Weak IP signal despite good input control. Low recovery of target protein compared to expected levels based on antibody quality.
Multiple specific bands appear at different molecular weights in IP lane. Input control shows same pattern, indicating genuine protein variants rather than non-specific binding.
Strong bands at approximately 50 kDa (heavy chain) and 25 kDa (light chain) obscure target protein signal. Same host species used for IP antibody and western blot detection antibody.
Multiple bands appear on western blot after IP. Background bands present in bead-only or IgG control lanes indicate non-specific binding.
No detectable signal in IP experiment. Input lysate control shows weak or absent target protein band on western blot.
No signal detected in co-immunoprecipitation experiment despite adequate protein expression confirmed by input lysate control. Western blot shows no target protein bands after IP.
IP experiment yields no detectable signal on western blot. Input lysate control shows weak or absent target protein bands, indicating expression below detection threshold.
IP of post-translationally modified proteins yields weak or no signal. Input lysate shows low basal levels of phosphorylated or modified target protein despite total protein presence.
IP shows weak target protein recovery despite adequate antibody concentration and protein expression. Bead pellet appears smaller than expected or shows poor antibody capture.
Multiple non-specific bands appear on western blot after IP. Background signal present in bead-only or isotype control lanes, indicating off-target protein capture.
Western blot after IP shows strong bands at ~25 kDa and ~50 kDa obscuring target protein. Target protein migrating near these molecular weights cannot be detected due to overwhelming IgG signal.
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