6dec

From Proteopedia

Crystal structure of Bos taurus Arp2/3 complex binding with C-terminus of Homo sapiens SPIN90

PDB ID 6dec

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Structural highlights

6dec is a 18 chain structure with sequence from Bos taurus and Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 4.6Å
Ligands:	,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

ARP3_BOVIN Functions as ATP-binding component of the Arp2/3 complex which is involved in regulation of actin polymerization and together with an activating nucleation-promoting factor (NPF) mediates the formation of branched actin networks. Seems to contact the pointed end of the daughter actin filament. Plays a role in ciliogenesis (By similarity).

Publication Abstract from PubMed

Unlike the WASP family of Arp2/3 complex activators, WISH/DIP/SPIN90 (WDS) family proteins activate actin filament nucleation by the Arp2/3 complex without the need for a preformed actin filament. This allows WDS proteins to initiate branched actin network assembly by providing seed filaments that activate WASP-bound Arp2/3 complex. Despite their important role in actin network initiation, it is unclear how WDS proteins drive the activating steps that require both WASP and pre-existing actin filaments during WASP-mediated nucleation. Here, we show that SPIN90 folds into an armadillo repeat domain that binds a surface of Arp2/3 complex distinct from the two WASP sites, straddling a hinge point that may stimulate movement of the Arp2 subunit into the activated short-pitch conformation. SPIN90 binds a surface on Arp2/3 complex that overlaps with actin filament binding, explaining how it could stimulate the same structural rearrangements in the complex as pre-existing actin filaments. By revealing how WDS proteins activate the Arp2/3 complex, these data provide a molecular foundation to understand initiation of dendritic actin networks and regulation of Arp2/3 complex by its activators.

Structure of the nucleation-promoting factor SPIN90 bound to the actin filament nucleator Arp2/3 complex.,Luan Q, Liu SL, Helgeson LA, Nolen BJ EMBO J. 2018 Oct 15. pii: embj.2018100005. doi: 10.15252/embj.2018100005. PMID:30322896^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Luan Q, Liu SL, Helgeson LA, Nolen BJ. Structure of the nucleation-promoting factor SPIN90 bound to the actin filament nucleator Arp2/3 complex. EMBO J. 2018 Oct 15. pii: embj.2018100005. doi: 10.15252/embj.2018100005. PMID:30322896 doi:http://dx.doi.org/10.15252/embj.2018100005