V.Angiosperm

Carpels are megasporophylls: produce megaspores that give rise to “female gametophytes”

TLS Online TPP Program

#Id: 8354

#XL - Q Biochemistry

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.

TLS Online TPP Program

#Id: 8353

#XL - Q Biochemistry

A second NPF is a large protein complex called WAVE

and requires small GTP-binding protein Rac1.

TLS Online TPP Program

#Id: 8351

#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

#Id: 8350

#XL - Q Biochemistry

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

TLS Online TPP Program

#Id: 8348

#XL - Q Biochemistry

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

TLS Online TPP Program

#Id: 8347

#XL - Q Biochemistry

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