Abstract
Neuronal Wiskott-Aldrich Syndrome protein (N-WASP) transmits signals from Cdc42 to the nucleation of actin filaments by Arp2/3 complex. Although full-length N-WASP is a weak activator of Arp2/3 complex, its activity can be enhanced by upstream regulators such as Cdc42 and PI(4,5)P2. We dissected this activation reaction and found that the previously described physical interaction between the NH2-terminal domain and the COOH-terminal effector domain of N-WASP is a regulatory interaction because it can inhibit the actin nucleation activity of the effector domain by occluding the Arp2/3 binding site. This interaction between the NH2- and COOH termini must be intramolecular because in solution N-WASP is a monomer. Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) influences the activity of N-WASP through a conserved basic sequence element located near the Cdc42 binding site rather than through the WASp homology domain 1. Like Cdc42, PI(4,5)P2 reduces the affinity between the NH2-and COOH termini of the molecule. The use of a mutant N-WASP molecule lacking this basic stretch allowed us to delineate a signaling pathway in Xenopus extracts leading from PI(4,5)P2 to actin nucleation through Cdc42, N-WASP, and Arp2/3 complex. In this pathway, PI(4,5)P2 serves two functions: first, as an activator of N-WASP; and second, as an indirect activator of Cdc42.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1299-1309 |
| Number of pages | 11 |
| Journal | Journal of Cell Biology |
| Volume | 150 |
| Issue number | 6 |
| DOIs | |
| State | Published - Sep 18 2000 |
| Externally published | Yes |
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Keywords
- Actin
- Cdc42 GTP-binding protein
- Phosphoinositides
- Signal transduction
- Wiskott-Aldrich Syndrome protein
ASJC Scopus subject areas
- Cell Biology
Cite this
Mechanism of N-WASP activation by CDC42 and phosphatidylinositol 4,5-bisphosphate. / Rohatgi, Rajat; Ho, Hsin-Yi Henry; Kirschner, Marc W.
In: Journal of Cell Biology, Vol. 150, No. 6, 18.09.2000, p. 1299-1309.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mechanism of N-WASP activation by CDC42 and phosphatidylinositol 4,5-bisphosphate
AU - Rohatgi, Rajat
AU - Ho, Hsin-Yi Henry
AU - Kirschner, Marc W.
PY - 2000/9/18
Y1 - 2000/9/18
N2 - Neuronal Wiskott-Aldrich Syndrome protein (N-WASP) transmits signals from Cdc42 to the nucleation of actin filaments by Arp2/3 complex. Although full-length N-WASP is a weak activator of Arp2/3 complex, its activity can be enhanced by upstream regulators such as Cdc42 and PI(4,5)P2. We dissected this activation reaction and found that the previously described physical interaction between the NH2-terminal domain and the COOH-terminal effector domain of N-WASP is a regulatory interaction because it can inhibit the actin nucleation activity of the effector domain by occluding the Arp2/3 binding site. This interaction between the NH2- and COOH termini must be intramolecular because in solution N-WASP is a monomer. Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) influences the activity of N-WASP through a conserved basic sequence element located near the Cdc42 binding site rather than through the WASp homology domain 1. Like Cdc42, PI(4,5)P2 reduces the affinity between the NH2-and COOH termini of the molecule. The use of a mutant N-WASP molecule lacking this basic stretch allowed us to delineate a signaling pathway in Xenopus extracts leading from PI(4,5)P2 to actin nucleation through Cdc42, N-WASP, and Arp2/3 complex. In this pathway, PI(4,5)P2 serves two functions: first, as an activator of N-WASP; and second, as an indirect activator of Cdc42.
AB - Neuronal Wiskott-Aldrich Syndrome protein (N-WASP) transmits signals from Cdc42 to the nucleation of actin filaments by Arp2/3 complex. Although full-length N-WASP is a weak activator of Arp2/3 complex, its activity can be enhanced by upstream regulators such as Cdc42 and PI(4,5)P2. We dissected this activation reaction and found that the previously described physical interaction between the NH2-terminal domain and the COOH-terminal effector domain of N-WASP is a regulatory interaction because it can inhibit the actin nucleation activity of the effector domain by occluding the Arp2/3 binding site. This interaction between the NH2- and COOH termini must be intramolecular because in solution N-WASP is a monomer. Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) influences the activity of N-WASP through a conserved basic sequence element located near the Cdc42 binding site rather than through the WASp homology domain 1. Like Cdc42, PI(4,5)P2 reduces the affinity between the NH2-and COOH termini of the molecule. The use of a mutant N-WASP molecule lacking this basic stretch allowed us to delineate a signaling pathway in Xenopus extracts leading from PI(4,5)P2 to actin nucleation through Cdc42, N-WASP, and Arp2/3 complex. In this pathway, PI(4,5)P2 serves two functions: first, as an activator of N-WASP; and second, as an indirect activator of Cdc42.
KW - Actin
KW - Cdc42 GTP-binding protein
KW - Phosphoinositides
KW - Signal transduction
KW - Wiskott-Aldrich Syndrome protein
UR - http://www.scopus.com/inward/record.url?scp=0034683746&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034683746&partnerID=8YFLogxK
U2 - 10.1083/jcb.150.6.1299
DO - 10.1083/jcb.150.6.1299
M3 - Article
VL - 150
SP - 1299
EP - 1309
JO - Journal of Cell Biology
JF - Journal of Cell Biology
SN - 0021-9525
IS - 6
ER -