Reconstitution of Human Arp2/3 Complex Reveals Critical Roles of Individual Subunits in Complex Structure and Activity
2001; Elsevier BV; Volume: 8; Issue: 5 Linguagem: Inglês
10.1016/s1097-2765(01)00393-8
ISSN1097-4164
AutoresHélène Gournier, Erin D. Goley, Hanspeter Niederstrasser, T. Michael Trinh, Matthew D. Welch,
Tópico(s)Cell Adhesion Molecules Research
ResumoThe Arp2/3 complex is a seven-protein assembly that is critical for actin nucleation and branching in cells. Here we report the reconstitution of active human Arp2/3 complex after expression of all seven subunits in insect cells. Expression of partial complexes revealed that a heterodimer of the p34 and p20 subunits constitutes a critical structural core of the complex, whereas the remaining subunits are peripherally located. Arp3 is crucial for nucleation, consistent with it being a structural component of the nucleation site. p41, p21, and p16 contribute differently to nucleation and stimulation by ActA and WASP, whereas p34/p20 bind actin filaments and likely function in actin branching. This study reveals that the nucleating and organizing functions of Arp2/3 complex subunits are separable, indicating that these activities may be differentially regulated in cells.
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