The coexistence of multiple alleles at a locus in a population is called genetic polymorphism. A locus is usually defined as polymorphic if two or more alleles are present at a frequency of more than 1% in the population.

TLS Online TPP Program

#Id: 9671

#Unit 4. Cell Communication and Cell Signaling

PH domain of PKB binds with high affinity to the 

3-phosphates in both PI(3,4)P2 and PI(3,4,5)P3

TLS Online TPP Program

#Id: 9672

#Unit 4. Cell Communication and Cell Signaling

In unstimulated cells, 

concentration of phosphoinositides is low, and PKB is

inactive because its PH domain physically blocks the kinase active site

TLS Online TPP Program

#Id: 9673

#Unit 4. Cell Communication and Cell Signaling

Ligand-induced receptor activation,

Concentration of PI 3-phosphates rises

PH domain of PKB binds to PI 3-phosphates

TLS Online TPP Program

#Id: 9674

#Unit 4. Cell Communication and Cell Signaling

Maximal activation of PKB depends on recruitment to the cytosolic surface of the plasma membrane of two other kinases -PDK1 and PDK2.

TLS Online TPP Program

#Id: 9675

#Unit 4. Cell Communication and Cell Signaling

PDK1 can phosphorylate PKB on a critical threonine residue in its activation loop

TLS Online TPP Program

#Id: 9676

#Unit 4. Cell Communication and Cell Signaling

Phosphorylation by the mTORC2 kinase complex, of a second serine on

PKB that is not in the activation loop is necessary for maximal PKB activity