In controlling the transport of molecules between the cytoplasm and the nucleus, nuclear import, and subsequent nuclear export, play critical roles in regulating many cellular processes. The nucleus contains the genetic material of a cell, including DNA and RNA, whilst the cytoplasm houses various organelles and is the site of many biochemical reactions. Efficient communication between these compartments is therefore critical for proper cell signalling and overall cell function. Nuclear import refers to the transport of molecules from the cytoplasm into the nucleus. This process is mediated through nuclear pore complexes (NPCs), large protein structures spanning the nuclear envelope. Protein import generally involves nuclear localization signals (NLSs) present on cargo protein molecules. NLSs are recognized by importin proteins which facilitate the translocation of cargo through the NPCs. Numerous signalling molecules utilize this type of nuclear import for their proper function. For example, in an inactive state, NF-κB is sequestered in the cytoplasm by its inhibitor, IκB. Upon activation by external signals such as cytokines or stress, IκB is phosphorylated and degraded, allowing NF-κB to expose its NLS. Importin proteins subsequently recognize the NLS, transporting NF-κB into the nucleus. Conversely, protein nuclear export involves the transportation of molecules from the nucleus to the cytoplasm. This process primarily relies on recognition of nuclear export signals (NESs) present on protein cargo molecules. Exportins, such as CRM1 (chromosome region maintenance 1), recognize NESs and facilitate the export of cargo through the NPCs. Cell signalling pathways often employ nuclear export to regulate gene expression and terminate signalling events. For example, the tumour suppressor protein p53, activated in response to DNA damage, translocates into the nucleus and induces the expression of genes involved in cell cycle arrest or apoptosis. p53 is then exported from the nucleus back to the cytoplasm, leading to the cessation of its transcriptional activity. Both nuclear import and export are essential for various aspects of cell signalling. They allow signalling molecules to translocate between the cytoplasm and nucleus, enabling them to regulate gene expression and initiate appropriate cellular responses. By controlling the access of genes to transcription factors, co-activators, and co-repressors, nuclear import and export tightly regulate gene transcription. Nuclear import and export are also involved in regulating the localization and activity of signalling proteins. For example, the MAPK (mitogen-activated protein kinase) signalling pathway plays a crucial role in cell proliferation and differentiation. Upon activation, MAPKs translocate to the nucleus to phosphorylate and modulate the activity of transcription factors, thereby influencing gene expression. For example, ERK phosphorylates Elk-1, a member of the ETS family of transcription factors, c-Fos, a component of the AP-1 (Activator Protein-1) transcription factor complex, c-Jun, another component of the AP-1 transcription factor complex and CREB (cAMP Response Element-Binding protein). Lastly, nuclear import and export contribute to the spatial and temporal regulation of signalling cascades. The transport of signalling molecules in and out of the nucleus allows for signal amplification, as a single molecule entering the nucleus can affect the transcription of multiple target genes. We offer a comprehensive product range of research tools for studying nuclear import and export, including MVP antibodies, Ran antibodies, NUP98 antibodies, KPNA4 antibodies, and SRP1 antibodies. Explore our full nuclear import and export product range below and discover more, for less.