1. Growth Hormone Receptor
Protein Structure
Growth Hormone Receptor

2. Normal Growth Hormone Receptor Activation
Growth hormone is believed to activate the growth hormone receptor (GHR) by dimerizing two identical receptor subunits, leading to activation of JAK2 kinase associated with the cytoplasmic receptor domain.
Erythropoietin Ligand Binding Receptor Superfamily
Members of this family interact with erythropoietin (EPO), inducing subsequent initiation of the chain of events associated with binding of EPO to the receptor, including EPO-induced erythroblast (nucleated erythrocyte) proliferation and differentiation through induction of the JAK2/STAT5 signaling cascade. The protein domain adopts a secondary structure composed of a short amino-terminal helix, followed by two beta-sandwich regions.

3. Insulin-Like Growth Factor I

4. Role of hIGF-1 in Laron Syndrome
Structure & Function
Human insulin-like growth factors I and II (hIGF-I, hIGF-II) are potent stimulators of cell and growth processes. They display high sequence similarity to both the A and B chains of insulin but contain an additional connecting C-domain. The human insulin-like growth factor structure features peptide-bond cleavage between Ser35 and Arg36 resulting in a gap between residues 35 and 39. The equivalent region of proinsulin is involved in hormone processing.
Role of hIGF-1 in Laron Syndrome
The somatomedins, or insulin-like growth factors (IGFs), comprise a family of peptides that play important roles in mammalian growth and development. hIGF-1 (Human Insulin-like Growth Factor 1) mediates many of the growth-promoting effects of growth hormone. Laron Syndrome results from failure to generate hIGF-1 due to dysfunction of the growth hormone receptor. Growth Hormone levels are normal or increased in affected individuals.

5. Growth Hormone Receptor Gene
The Growth Hormone Receptor Gene encodes a protein that is a transmembrane receptor for growth hormone. Binding of growth hormone to the receptor leads to receptor dimerization and the activation of an intra- and intercellular signal transduction pathway leading to growth. Mutations in this gene have been associated with Laron syndrome, also known as growth hormone insensitivity syndrome (GHIS).

6. Case Studies

7. Conclusion

8. Refrences