RII phosphorylates serine and threonine in the juxtamembrane segment of the RI (ligand induced receptor hetero-oligomerization), releasing the inhibition of RI kinase activity.

TLS Online TPP Program

#Id: 8632

#XL - T Zoology

Substrate-targeting subunits of the APC/C recognize specific sequence motifs on the proteins that the APC/C ubiquitinates. One motif, the destruction box or D-box, has the consensus sequence

RXXLX[D/E]ΦΦΦXN[N/S]

TLS Online TPP Program

#Id: 8633

#XL - T Zoology

Mutating or deleting the destruction box in mitotic cyclins prevented their ubiquitination and blocked cells from exiting mitosis.

TLS Online TPP Program

#Id: 8634

#XL - T Zoology

At the metaphase to anaphase transition, APC/C bound to Cdc20 targets cyclins A /B and securin for degradation.

TLS Online TPP Program

#Id: 8635

#XL - T Zoology

During late anaphase, telophase and G1, APC/C bound to Cdh1 targets B type cyclins and geminin for degradation.

TLS Online TPP Program

#Id: 8637

#XL - T Zoology

The G1 cyclin-CDK complex (Cln3-CDK in yeast) stimulates the formation of G1/S phase cyclin-CDKs, which initiate bud formation, centrosome duplication, and DNA replication.

TLS Online TPP Program

#Id: 8638

#XL - T Zoology

Once sufficient Cln3 is synthesized from its mRNA, Cln3-CDK complexes phosphorylate and inactivate the transcriptional repressor Whi5.