Question

Describe what is meant by 'inside-outside-in' crosstalk and the involvement of G proteins?

Answer 1

Cellular signaling carried through various types of biochemical mechanisms which involves the neurotransmitters, hormones, and chemokines. In signaling pathway there are the receptors on the cell surface that helps in detection of cellular signals. In Plasma membrane of there are trans-membrane proteins. When molecules bind with receptors such as G protein, tyrosine kinase and intergin on cell surface these receptors further transcribe the signal with help of trans-membrane proteins.

Inside-outside-in cross talk defines the cellular signaling from inside of cell to outside and vice versa.

G Protein-Coupled receptor (GPCR) initiates the intracellular signaling process with help of different types of ligands. In cellular cross talk there is requirement of both G proteins i.e. hetero-trimetric and small G proteins. These G Proteins are guanosine triphophatases which recycle the GDP and GTP form. In GTP form the G protein is in active state where it interacts with downstream molecules and transmits the signals. In this process the GTP get hydrolyzed to GDP and GDP form is the inactive form of G protein. This regulation of G protein regulated with help of three proteins i.e. GTPase-activating proteins, guanine nucleotide-exchange factors and dissociation inhibitors