TLS Online TPP Program

#Id: 9086

#XL - T Zoology

A1 associates with ARF6, a small G protein in host cells which are accessible only when ARF6 is in its active (GTP-bound) form. 

TLS Online TPP Program

#Id: 9087

#XL - T Zoology

Association with ARF6 activates A1, which catalyzes the transfer of ADP-ribose from NAD to the critical Arg residue in the P loop of the  subunit of Gαs. 

TLS Online TPP Program

#Id: 9088

#XL - T Zoology

TLS Online TPP Program

#Id: 9089

#XL - T Zoology

ADP-ribosylation blocks the GTPase activity of Gαs and renders Gαs permanently active. 

TLS Online TPP Program

#Id: 9090

#XL - T Zoology

This results in continuous activation of the AC of intestinal epithelial cells, chronically active PKA which phosphorylates the CFTR Cl- channel and a Na-H exchanger in the intestinal epithelial cells. 

TLS Online TPP Program

#Id: 9091

#XL - T Zoology

The resultant efflux of NaCl triggers massive water loss through the intestine as cells respond to the ensuing osmotic imbalance causes severe dehydration and electrolyte loss.