Question

Conserved domains in signal transduction pathways:

a) What is a domain?

b) List three domains commonly found in signal transduction and briefly describe each one

Answer 1

Answere :

a). Domain is a compact, globular region of a protein that form the basic unit of tertiary structure. Small proteins such as ribonuclease or myoglobin, contain a single domain; larger protein may contain a number of differential domain, which have distint function.

b). In signal transduction, there are binding domain as well as well as enzymatic/catalytic domain. Example : kinase domain is a catalytic domain whereas PH domain (pleckstrin homology domain),  PTB domain (phosphotyrosine-binding domain), SH2 and SH3 domains (src homology 2 and 3 domains) are binding domain.

SH2 domain binds phosphorylated tyrosine.

SH3 domain binds hydrophobic proline residue.

PTB domain also bind phosphotyrosine.