In the dark, PEPCase returns to the inactive form because PEPCase‐kinase is inactivated and a phosphatase releases the phosphoryl group from PEPCase.

TLS Online TPP Program

#Id: 9700

#Unit 4. Cell Communication and Cell Signaling

Mating pathway in the yeast S. cerevisiae, is a MAP kinase cascade which linked to GPCRs.

TLS Online TPP Program

#Id: 9701

#Unit 4. Cell Communication and Cell Signaling

Two mating types of yeast cells are: 

1. a 

2. α

TLS Online TPP Program

#Id: 9702

#Unit 4. Cell Communication and Cell Signaling

Haploid yeast cells secrete protein signals known as pheromones, which induce mating between opposite mating types.

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#Id: 9703

#Unit 4. Cell Communication and Cell Signaling

An a haploid cell secretes the a mating factor and has GPCRs for the α factor on its cell surface; an α cell secretes the α factor and has GPCRs for the a factor.

TLS Online TPP Program

#Id: 9704

#Unit 4. Cell Communication and Cell Signaling

Activation of the MAP kinase pathway by either the a or the α GPCRs induces transcription of genes that inhibit progression of the cell cycle

TLS Online TPP Program

#Id: 9705

#Unit 4. Cell Communication and Cell Signaling

The receptors for yeast α and a mating factors are coupled to the same trimeric G protein.