Auxins in biological samples can be determined by bioassay, mass spectrometry, or enzyme-linked immunosorbent assay (ELISA).

The Avena coleoptile curvature assay is a sensitive measure of auxin activity (it is effective for IAA concentrations of about 0.02 to 0.2 mg L–1).

TLS Online TPP Program

#Id: 1394

#Unit 4. Cell Communication and Cell Signaling

CapZ blocks the (+) end, which is where filaments normally grow, so its function is to limit actin dynamics to the (−) end.

TLS Online TPP Program

#Id: 1395

#Unit 4. Cell Communication and Cell Signaling

Tropomodulin blocks (−) ends, where filament disassembly normally occurs; thus the major function of tropomodulin is to stabilize filaments .

TLS Online TPP Program

#Id: 1396

#Unit 4. Cell Communication and Cell Signaling

All small GTPases of the Ras superfamily, Cdc42, Rac, and Rho act as molecular switches, inactive in the GDP-bound state and active in the GTP-bound state.

TLS Online TPP Program

#Id: 1397

#Unit 4. Cell Communication and Cell Signaling

Actin-based motors powered by ATP hydrolysis.

TLS Online TPP Program

#Id: 1398

#Unit 4. Cell Communication and Cell Signaling

Myosins have 

  Motor head domain

  Lever-arm neck domain

  Cargo-binding tail domain

TLS Online TPP Program

#Id: 1399

#Unit 4. Cell Communication and Cell Signaling

The first myosin discovered

Myosin II, was isolated from skeletal muscle.