Cellular Retinoic Acid binding Protein 1 Human Recombinant
Cellular Retinoic Acid binding Protein 2 Human Recombinant
Cellular Retinoic Acid Binding Proteins (CRABPs) are a family of intracellular proteins that bind retinoic acid (RA) with high affinity. They are part of the calycin superfamily of fatty acid binding proteins and play a crucial role in the transport and regulation of retinoic acid within cells . There are two main isoforms of CRABP: CRABP-I and CRABP-II, each encoded by distinct genes and exhibiting different expression patterns and functions .
Key Biological Properties: CRABPs are small, cytoplasmic proteins that specifically bind all-trans-retinoic acid (ATRA) and facilitate its transport to the nucleus . They are highly conserved across species, indicating their essential role in cellular processes.
Expression Patterns: CRABP-I is ubiquitously expressed in various tissues, while CRABP-II has a more restricted expression pattern, being predominantly found in the skin, brain, and certain epithelial tissues .
Tissue Distribution: CRABP-I is widely distributed in tissues such as the liver, kidney, and heart, whereas CRABP-II is mainly localized in the skin and central nervous system .
Primary Biological Functions: CRABPs are involved in the regulation of retinoic acid signaling, which is crucial for cell differentiation, proliferation, and apoptosis . They act as carriers, delivering retinoic acid to nuclear receptors, thereby influencing gene expression.
Role in Immune Responses and Pathogen Recognition: CRABPs play a role in modulating immune responses by regulating the availability of retinoic acid, which is known to influence the differentiation and function of immune cells .
Mechanisms with Other Molecules and Cells: CRABPs interact with retinoic acid receptors (RARs) and retinoid X receptors (RXRs) in the nucleus to regulate gene transcription . They also interact with other cytoplasmic proteins to modulate intracellular retinoic acid levels .
Binding Partners and Downstream Signaling Cascades: CRABPs bind to retinoic acid and facilitate its transport to the nucleus, where it binds to RARs and RXRs. This binding initiates a cascade of gene transcription events that regulate various cellular processes .
Transcriptional Regulation: The expression of CRABP genes is regulated by retinoic acid itself, as well as other factors such as thyroid hormones . The CRABP-I gene is driven by a housekeeping promoter, while the CRABP-II gene contains a TATA-box and is rapidly activated by retinoic acid .
Post-Translational Modifications: CRABPs undergo various post-translational modifications that can influence their stability, localization, and interaction with other proteins .
Biomedical Research: CRABPs are used as markers to study retinoic acid signaling pathways and their role in development and disease .
Diagnostic Tools: CRABPs can serve as biomarkers for certain diseases, including cancers and skin disorders, due to their altered expression patterns in these conditions .
Therapeutic Strategies: Targeting CRABPs with retinoic acid-like compounds has potential therapeutic applications in treating diseases such as cancer and neurodegenerative disorders .
Development: CRABPs are essential for embryonic development, particularly in the formation of the central nervous system and other organs .
Aging and Disease: The expression and function of CRABPs can change with age, and dysregulation of CRABP-mediated retinoic acid signaling is associated with various diseases, including cancer and neurodegenerative disorders .