Question

Difference between intrinsic tyrosine kinase and receptor associated tyrosine kinase

Answer 1

Nonreceptor tyrosine kinase receptors dimerizes -> recruits JAK -> JAK cross-phosphorylate dimer -> activate STAT and dimerize it -> STAT translocates into nucleus and activates transcription. The hormones are mostly related to immunity. Think acidophils and cytokines. A good mnemonic is PIGG(L)ET: Prolactin, Immunomodulators (cytokine, IL-2, Il-6, IFN), GH, G-CSF, Erythropoietin and Thromobopoietin

The key conceptual difference here is RTK has intrinsic TK activity and nRTK needs to recruit JAK to have kinase activity.

Answer 2

Answer:

Although all cell membrane receptors receive and transmit signals from the environment, some of these receptors also double as enzymes. In such cases, the binding of a signaling molecule to the membrane receptor activates the receptor's inherent enzymatic activity. Of the various receptors that exhibit this capability, receptor tyrosine kinases (RTKs) make up the largest class. These cell surface receptors bind and respond to growth factors and other locally released proteins that are present at low concentrations. RTKs play important roles in the regulation of cell growth, differentiation, and survival.

When signaling molecules bind to RTKs, they cause neighboring RTKs to associate with each other, forming cross-linked dimers. Cross-linking activates the tyrosine kinase activity in these RTKs through phosphorylation — specifically, each RTK in the dimer phosphorylates multiple tyrosines on the other RTK. This process is called cross-phosphorylation.