Regulation of INF2-mediated actin polymerization through site-specific lysine acetylation of actin itself
| Autor: | Thao Huynh, Henry N. Higgs, Zdenek Svindrych, Lisa M. Francomacaro, Mu A, Tommi Kotila, Tak Shun Fung |
|---|---|
| Přispěvatelé: | Institute of Biotechnology, Doctoral Programme in Integrative Life Science |
| Rok vydání: | 2019 |
| Předmět: |
MECHANISM
Glutamine LEVEL Mutant Cell Cycle Proteins MONOMERS medicine.disease_cause 0302 clinical medicine U2OS 0303 health sciences Mutation Multidisciplinary biology Chemistry COFILIN Acetylation Biological Sciences Cofilin Cell biology mitochondria Actin Cytoskeleton Formins WH2 motif nucleation macromolecular substances cyclase-associated protein 03 medical and health sciences Protein Domains Cell Line Tumor medicine Humans Actin Adaptor Proteins Signal Transducing 030304 developmental biology Lysine Membrane Proteins INVERTED FORMIN 2 Actins INF2 Cytoskeletal Proteins Amino Acid Substitution WH2 DOMAIN biology.protein 1182 Biochemistry cell and molecular biology ADP-ACTIN 030217 neurology & neurosurgery |
| Zdroj: | Proc Natl Acad Sci U S A |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.1914072117 |
| Popis: | INF2 is a formin protein that accelerates actin polymerization. A common mechanism for formin regulation is autoinhibition, through interaction between the N-terminal diaphanous inhibitory domain (DID) and C-terminal diaphanous autoregulatory domain (DAD). We recently showed that INF2 uses a variant of this mechanism that we term "facilitated autoinhibition," whereby a complex consisting of cyclase-associated protein (CAP) bound to lysine-acetylated actin (KAc-actin) is required for INF2 inhibition, in a manner requiring INF2-DID. Deacetylation of actin in the CAP/KAc-actin complex activates INF2. Here we use lysine-to-glutamine mutations as acetylmimetics to map the relevant lysines on actin for INF2 regulation, focusing on K50, K61, and K328. Biochemically, K50Q- and K61Q-actin, when bound to CAP2, inhibit full-length INF2 but not INF2 lacking DID. When not bound to CAP, these mutant actins polymerize similarly to WT-actin in the presence or absence of INF2, suggesting that the effect of the mutation is directly on INF2 regulation. In U2OS cells, K50Q- and K61Q-actin inhibit INF2-mediated actin polymerization when expressed at low levels. Direct-binding studies show that the CAP WH2 domain binds INF2-DID with submicromolar affinity but has weak affinity for actin monomers, while INF2-DAD binds CAP/K50Q-actin 5-fold better than CAP/WT-actin. Actin in complex with full-length CAP2 is predominately ATP-bound. These interactions suggest an inhibition model whereby CAP/KAc-actin serves as a bridge between INF2 DID and DAD. In U2OS cells, INF2 is 90-fold and 5-fold less abundant than CAP1 and CAP2, respectively, suggesting that there is sufficient CAP for full INF2 inhibition. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|