In the CCR4-Not world, there are endless aspects that deserve to be explored and discussed. Whether CCR4-Not is a person, a topic, a date or any other concept, its relevance and impact on our lives become evident as we delve deeper into its meaning and repercussions. From its origin to its evolution over time, CCR4-Not has left its mark on society, culture and history, generating debates, reflections and analyzes that allow us to better understand its importance. In this article, we will delve into the world of CCR4-Not to discover its many facets and learn more about its meaning in our current context.
Multiprotein complex used in gene expression
Structure of human CNOT1-CNOT2-CNOT3 module (PDB 4C0D).[1]
Carbon Catabolite Repression 4—Negative On TATA-less, or CCR4-Not, is a multiprotein complex that functions in gene expression.[2][3] The complex has multiple enzymatic activities as both a poly(A) 3′-5′ exonuclease and a ubiquitin ligase.[4][5][6][7] The exonuclease activity of CCR4-Not shortens the poly(A) tail found at 3' end of almost every eukaryotic mRNA.[8] The complex is present both in the nucleus where it regulates transcription and in the cytoplasm where it associates with translating ribosomes and RNA processing bodies.[2][3] In mammalian cell, it has a function in the regulation of the cell cycle, chromatin modification, activation and inhibition of transcription initiation, control of transcription elongation, RNA export, nuclear RNA surveillance, and DNA damage repair in nucleus. Ccr4–Not complex plays an important role in mRNA decay and protein quality control in the cytoplasm.[9]
Subunits
The human CCR4-Not complex is composed of structural (non-catalytic) subunits and those that have exonuclease and E3 ligase activity. Some but not all of the human subunits are conserved in budding yeast.[10] In yeast the complex has nine core subunits, comprising Ccr4 (carbon catabolite repression), Caf proteins (Ccr4 associated factor) (Caf1, Caf40, Caf130) and Not proteins (Not1, Not2, Not3, Not4, and Not5).[11]
^Boland, Andreas; Chen, Ying; Raisch, Tobias; Jonas, Stefanie; Kuzuoğlu-Öztürk, Duygu; Wohlbold, Lara; Weichenrieder, Oliver; Izaurralde, Elisa (2013-10-13). "Structure and assembly of the NOT module of the human CCR4–NOT complex". Nature Structural & Molecular Biology. 20 (11). Springer Science and Business Media LLC: 1289–1297. doi:10.1038/nsmb.2681. ISSN1545-9993. PMID24121232. S2CID24288483.