Question

While studying the function of a G protein-coupled receptor you develop a modified GTP molecule that has the same binding capabilities as GTP but cannot be hydrolyzed to GDP + Pi. What effect would this molecule have if added to your GPCR signaling pathway?

Answer 1

Answer:

Effects Include:

Activates secondary messengers such as cAMP which further activates number of hormones like

• ADH: production of this hormone causes kidneys to retain more water inside body.

• GHRH: release growth factors and stimulates growth of organism.

• ACTH: produces fight or flight responses i.e rise in heart beat, rise in Blood pressure etc

• TSH: Stimulate the synthesis of Thyroid hormone and enhances the metabolism of body. In rare cases causes Goiter without the deficiency of Iodine.

• LH: Stimulate follicle maturation and formation of ovules in women.

• Calcitonin: Decreases blood calcium level by deposition calcium in bones. This effect weakens the muscles.

• Glucagon: Stimulates glycogen breakdown from liver and muscles and many more effects.

Explanation:

Background Knowledge:

GPCR (G Protien coupled receptors) are present inside plasma membrane in huge amount. As name suggest that these receptors are coupled with G proteins during their inactive state present inside of the cell. During their Inactive state these G proteins are bounded with GDP molecule.

Upon receiving signal molecules from outside of cell alters the shape of GPCR. These receptors also triggers change in G Protein, as a result of this GTP get attached with them. This protein further activates reaction cascades inside of the cell.

What happen if GTP cannot be hydrolyzed to GDP + Pi?

If GTP cannot hydrolyzed in to GDP + Pi than, it cannot be able to dissociate from G proteins. Cascade system doesn't stop and produces many effects on body.

Effects Include:

Activates secondary messengers such as cAMP which further activates number of hormones like

• ADH: production of this hormone causes kidneys to retain more water inside body.

• GHRH: release growth factors and stimulates growth of organism.

• ACTH: produces fight or flight responses i.e rise in heart beat, rise in Blood pressure etc

• TSH: Stimulate the synthesis of Thyroid hormone and enhances the metabolism of body. In rare cases causes Goiter without the deficiency of Iodine.

• LH: Stimulate follicle maturation and formation of ovules in women.

• Calcitonin: Decreases blood calcium level by deposition calcium in bones. This effect weakens the muscles.

• Glucagon: Stimulates glycogen breakdown from liver and muscles and many more effects.