Actin can reversibly assemble into filaments that consist of two helices of actin subunits

TLS Online TPP Program

#Id: 8357

#Section 3: Genetics, Cellular and Molecular Biology

VASP 

has a proline-rich

hold onto the end of the newly formed filament

protect the end of the growing filament from CapZ

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#Id: 8356

#Section 3: Genetics, Cellular and Molecular Biology

ActA protein binds the host protein VASP, which enhance actin assembly and confine it to the rear of the bacterium.

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#Id: 8354

#Section 3: Genetics, Cellular and Molecular Biology

Listeria is a food-borne bacterial pathogen has on its surface a protein ActA, which mimics an NPF that efficiently activates the Arp2/3 complex.

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#Id: 8353

#Section 3: Genetics, Cellular and Molecular Biology

A second NPF is a large protein complex called WAVE

and requires small GTP-binding protein Rac1.

TLS Online TPP Program

#Id: 8351

#Section 3: Genetics, Cellular and Molecular Biology

WASp activation requires two signals (This type of two-signal input, called coincidence detection):

1. regulatory phospholipid PIP2

2. small GTP-binding protein Cdc42

TLS Online TPP Program

#Id: 8350

#Section 3: Genetics, Cellular and Molecular Biology

One NPF is called WASp, as it is defective in patients with Wiskott-Aldrich syndrome.