Receptor tyrosine kinases (RTKs) are activated by ligand binding which induces dimerization and downstream effects on gene transcription. Dominant negative receptor mutants can block wild type receptor activity and are useful for studying signal transduction pathways. Allostery allows biological macromolecules to transmit binding effects between sites, regulating signal transduction pathway components based on cellular status.

1. 1. All RTKs have a similar molecular architecture, with a ligand-binding region in the
extracellular domain, a single transmembrane helix, and a cytoplasmic region that contains the
protein tyrosine kinase (TK) domain plus additional carboxy (C-) terminal and juxtamembrane
regulatory regions. In general, growth factor binding activates RTKs by inducing receptor
dimerization, (Ullrich, 1990). Further, extracellular matrix proteins and certain surface proteins
on neighboring cells can also bind to and activate RTKs. The down stream effect is:molecules
direct cell differentiation by determining patterns of gene transcription.
2.The dominant negative receptor mutants which atlow concentrations, are capable of blocking
the intracellular activity of wild type e.g estrogen receptor (ER) mutants as reported by(Ince,
1993). Such mutants are useful in studying the pathway of signal transduction after receptor
activation.
3. Allostery is the process by which biological macromolecules (mostly proteins) transmit the
effect of binding at one site to another, often distal, functional site, allowing for regulation of
activity. Hence by allostery the components of the signal transduction pathway may be inhibited
or activated depending on the status of the cell i.e. regulated
Solution
1. All RTKs have a similar molecular architecture, with a ligand-binding region in the
extracellular domain, a single transmembrane helix, and a cytoplasmic region that contains the
protein tyrosine kinase (TK) domain plus additional carboxy (C-) terminal and juxtamembrane
regulatory regions. In general, growth factor binding activates RTKs by inducing receptor
dimerization, (Ullrich, 1990). Further, extracellular matrix proteins and certain surface proteins
on neighboring cells can also bind to and activate RTKs. The down stream effect is:molecules
direct cell differentiation by determining patterns of gene transcription.
2.The dominant negative receptor mutants which atlow concentrations, are capable of blocking
the intracellular activity of wild type e.g estrogen receptor (ER) mutants as reported by(Ince,
1993). Such mutants are useful in studying the pathway of signal transduction after receptor
activation.
3. Allostery is the process by which biological macromolecules (mostly proteins) transmit the
effect of binding at one site to another, often distal, functional site, allowing for regulation of
activity. Hence by allostery the components of the signal transduction pathway may be inhibited
or activated depending on the status of the cell i.e. regulated