Open Access Gold möglich sobald Verlagsversion bei der ZB eingereicht worden ist.
Membrane targeting of the Spir-formin actin nucleator complex requires a sequential handshake of polar interactions.
J. Biol. Chem. 290, 6428-6444 (2015)
Spir and formin (FMN)-type actin nucleators initiate actin polymerization at vesicular membranes necessary for long range vesicular transport processes. Here we studied in detail the membrane binding properties and protein/protein interactions that govern the assembly of the membrane-associated SpirFMN complex. Using biomimetic membrane models we show that binding of the C-terminal Spir-2 FYVE-type zinc finger involves both the presence of negatively charged lipids and hydrophobic contributions from the turret loop that intrudes the lipid bilayer. In solution, we uncovered a yet unknown intramolecular interaction between the Spir-2 FYVE-type domain and the N-terminal kinase non-catalytic C-lobe domain (KIND) that could not be detected in the membrane-bound state. Interestingly, we found that the intramolecular Spir-2 FYVE/KIND and the trans-regulatory Fmn-2-FSI/Spir-2-KIND interactions are competitive. We therefore characterized co-expressed Spir-2 and Fmn-2 fluorescent protein fusions in living cells by fluorescence cross-correlation spectroscopy. The data corroborate a model according to which Spir-2 exists in two different states, a cytosolic monomeric conformation and a membrane-bound state in which the KIND domain is released and accessible for subsequent Fmn-2 recruitment. This sequence of interactions mechanistically couples membrane binding of Spir to the recruitment of FMN, a pivotal step for initiating actin nucleation at vesicular membranes.
Impact Factor
Scopus SNIP
Altmetric
4.573
1.208
Anmerkungen
Besondere Publikation
Auf Hompepage verbergern
Publikationstyp
Artikel: Journalartikel
Dokumenttyp
Wissenschaftlicher Artikel
Schlagwörter
Fluorescence Correlation Spectroscopy; Cross-correlation Spectroscopy; Fyve Domain; Phosphatidylinositol 3-phosphate; Cellular Membranes; Vesicle Transport; Crystal-structure; Kinase Function; C-lobe; Protein
Sprache
englisch
Veröffentlichungsjahr
2015
HGF-Berichtsjahr
0
ISSN (print) / ISBN
0021-9258
e-ISSN
1083-351X
Zeitschrift
Journal of Biological Chemistry, The
Quellenangaben
Band: 290,
Heft: 10,
Seiten: 6428-6444
Verlag
American Society for Biochemistry and Molecular Biology
Verlagsort
Bethesda
Begutachtungsstatus
Peer reviewed
Institut(e)
German Center for Diabetes Reseach (DZD)
WOS ID
WOS:000350732500047
Erfassungsdatum
2015-04-13