Matrix-targeting sequences

Located at the N-terminus

Usually 20–50 amino acids in length

Rich in hydrophobic amino acids, positively charged basic amino acids (arginine & lysine), and hydroxylated ones (serine and threonine)

Amphipathicity of matrix-targeting sequences is critical to their function

TLS Online TPP Program

#Id: 9678

#Unit 4. Cell Communication and Cell Signaling

Activated PKB also promotes survival of many cultured cells by phosphorylating the Forkhead transcription factor FOXO3a on multiple serine and threonine residues.

TLS Online TPP Program

#Id: 9679

#Unit 4. Cell Communication and Cell Signaling

The cytosolic phosphoserine binding protein 14-3-3 then binds to phosphorylated FOXO3a and sequesters it in the cytosol.

TLS Online TPP Program

#Id: 9680

#Unit 4. Cell Communication and Cell Signaling

A FOXO3a mutant in which the three serine residues that are targets for PKB are mutated to alanines is constitutively active

TLS Online TPP Program

#Id: 9681

#Unit 4. Cell Communication and Cell Signaling

PI-3 kinase signaling pathway is terminated by

PTEN phosphatase, which hydrolyzes the 3-phosphate

in PI 3-phosphates.

TLS Online TPP Program

#Id: 9682

#Unit 4. Cell Communication and Cell Signaling

PTEN can remove phosphate groups attached to serine,

threonine, and tyrosine residues in proteins, its ability to

remove the 3-phosphate from PI(3,4,5)P3 is its major function in cells.

TLS Online TPP Program

#Id: 9683

#Unit 4. Cell Communication and Cell Signaling

Loss of the PTEN protein contributes to the uncontrolled growth of cells.