Cellular retinoic acid-binding protein (CRABP) (CRABP)

Cellular retinoic acid-binding proteins (CRABPs) are small cytosolic proteins that function as intracellular chaperones for all-trans-retinoic acid (atRA), the primary active metabolite of vitamin A (Source: NIH). The family consists of two main isoforms, CRABP1 and CRABP2, which exhibit high affinity for atRA but serve distinct physiological roles (Source: UniProt). CRABP2 is primarily responsible for transporting atRA from the cytoplasm into the nucleus, where it facilitates the transfer of the ligand to retinoic acid receptors (RARs) to initiate gene transcription (Source: PubMed). Conversely, CRABP1 is involved in sequestering atRA and directing it toward catabolic enzymes, such as CYP26, while also participating in non-canonical signaling by modulating cytosolic kinases like CaMKII and ERK (Source: MDPI). Dysregulation of these proteins is frequently observed in various cancers, including breast and lung cancer, where they can influence tumor progression, metastasis, and sensitivity to retinoid therapy (Source: NIH). Furthermore, CRABPs have emerged as potential therapeutic targets for neurodegenerative diseases like ALS and cardiovascular conditions due to their roles in regulating cell survival and stress responses (Source: PubMed). Targeting CRABPs with selective ligands offers a promising strategy to modulate retinoid signaling while minimizing the systemic toxicity often associated with direct RAR activation (Source: MDPI).

Other names

CRABP1CRABP2CRABP-ICRABP-IIRBP5Cellular retinoic acid-binding protein 1Cellular retinoic acid-binding protein 2

Facilitates the intracellular transport of retinoic acid to nuclear receptors or catabolic enzymes and modulates non-canonical signaling pathways through interaction with cytosolic kinases.