MICAL proteins play a crucial role in cellular dynamics by binding and disassembling actin filaments, impacting processes like axon guidance, cytokinesis, and cell morphology. Their cellular activity is tightly controlled, as dysregulation can lead to detrimental effects on cellular morphology. Although previous studies have suggested that MICALs are autoinhibited, and require Rab proteins to become active, the detailed molecular mechanisms remained unclear. Here, we report the cryo-EM structure of human MICAL1 at a nominal resolution of 3.1 Å. Structural analyses, alongside biochemical and functional studies, show that MICAL1 autoinhibition is mediated by an intramolecular interaction between its N-terminal catalytic and C-terminal coiled-coil domains, blocking F-actin interaction. Moreover, we demonstrate that allosteric changes in the coiled-coil domain and the binding of the tripartite assembly of CH-L2α1-LIM domains to the coiled-coil domain are crucial for MICAL activation and autoinhibition. These mechanisms appear to be evolutionarily conserved, suggesting a potential universality across the MICAL family.

• MeSH
• aktiny metabolismus   chemie   MeSH
• alosterická regulace MeSH
• calponiny MeSH
• elektronová kryomikroskopie * MeSH
• lidé MeSH
• mikrofilamenta metabolismus   ultrastruktura   MeSH
• mikrofilamentové proteiny metabolismus   chemie   ultrastruktura   MeSH
• molekulární modely MeSH
• oxygenasy se smíšenou funkcí MeSH
• proteinové domény MeSH
• proteiny s doménou LIM metabolismus   chemie   genetika   MeSH
• vazba proteinů * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

A precisely balanced activity of canonical Wnt signaling is essential for a number of biological processes and its perturbation leads to developmental defects or diseases. Here, we demonstrate that alternative isoforms of the KDM2A and KDM2B lysine demethylases have the ability to negatively regulate canonical Wnt signaling. These KDM2A and KDM2B isoforms (KDM2A-SF and KDM2B-SF) lack the N-terminal demethylase domain, but they still have the ability to bind to CpG islands in promoters and to interact with their protein partners via their other functional domains. We have observed that KDM2A-SF and KDM2B-SF bind to the promoters of axin 2 and cyclin D1, two canonical Wnt signaling target genes, and repress their activity. Moreover, KDM2A-SF and KDM2B-SF are both able to strongly repress a Wnt-responsive luciferase reporter. The transcriptional repression mediated by KDM2A-SF and KDM2B-SF, but also by KDM2A-LF, is dependent on their DNA binding domain, while the N-terminal demethylase domain is dispensable for this process. Surprisingly, KDM2B-LF is unable to repress both the endogenous promoters and the luciferase reporter. Finally, we show that both KDM2A-SF and KDM2B-SF are able to interact with TCF7L1, one of the transcriptional mediators of canonical Wnt signaling. KDM2A-SF and KDM2B-SF are thus likely to negatively affect the transcription of canonical Wnt signaling target genes by binding to their promoters and by interacting with TCF7L1 and other co-repressors.

• MeSH
• CpG ostrůvky MeSH
• cyklin D1 genetika   metabolismus   MeSH
• F-box proteiny genetika   metabolismus   MeSH
• HEK293 buňky MeSH
• Jumonjiho doména s histondemethylasami genetika   metabolismus   MeSH
• lidé MeSH
• lysin genetika   metabolismus   MeSH
• promotorové oblasti (genetika) * MeSH
• protein - isoformy MeSH
• protein 1 podobný transkripčnímu faktoru 7 genetika   metabolismus   MeSH
• regulace genové exprese * MeSH
• signální dráha Wnt * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH