IFN-ϒ acts directly by inducing an antiviral state in nearby cells.

IL-2 acts indirectly by assisting the development of cytotoxic T lymphocyte(CTL) precursors into an effector population.

Both IL-2 and IFN-ϒ activate NK cells.

TLS Online TPP Program

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#XL - Q Biochemistry

A second NPF is a large protein complex called WAVE

and requires small GTP-binding protein Rac1.

TLS Online TPP Program

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#XL - Q Biochemistry

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

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#XL - Q Biochemistry

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

TLS Online TPP Program

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#XL - Q Biochemistry

The major NPF family is characterized by the presence of a region called WCA (WH2, connector, acidic)

TLS Online TPP Program

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#XL - Q Biochemistry

To nucleate the assembly of branched actin filaments, Arp2/3 needs to be activated by a nucleation promoting factor (NPF)

TLS Online TPP Program

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#XL - Q Biochemistry

Formins are activated by membrane-bound Rho-GTP, a Ras-related small GTPase