Serine-threonine-specific receptor protein kinases

The epinephrine receptor causes the synthesis of cyclic AMP, which is an activator of an enzyme, a protein kinase C (see Figure 12-11). Protein kinases transfer phosphate from ATP to the hydroxyl group on the side chain of a serine, threonine, or tyrosine. Protein kinase C is a serine-specific kinase. Protein kinase C is a tettamer composed of two regulatory (R) subunits and two catalytic (C) subunits. When it has cAMP bound to it, the R subunit dissociates from the C subunits. The C subunits are now catalytically active. 

Receptor Serine/Threonine Receptor Protein Kinase = Receptor Protein Phosphotyrosine Phosphatase = Receptor Tyrosine Kinase = Signal Transducer and Activator of Transcription = Transforming Growth Factor P = Tetradecanoylphorbolacetate = Tetradecanoylphorbolacetate Response Element = Change in Permeability of PM to specific solutes = Change in Transmembrane Potential. 

Protein tyrosine phosphatases. Phosphoprotein phosphatases are integral components of the signahng systems operated by protein kinases (Sun and Tonks, 1994). Cloning data show the protein tyrosine phosphatases (PTPs) to be a family of multidomain proteins having exceptional diversity. They can be broadly divided into two groups, the transmembrane or receptor-like PTPs and the cytosolic PTPs. None of these are related to the serine-threonine specific phosphatases. This is in contrast to the protein kinases (Seer-Thr and Tyr specific), which share a common ancestry. Unlike the Ser-Thr phosphatases, in which substrate specificity is determined by associated targeting subunits, the Tyr phosphatases are all monomeric enzymes. 

A new signaling pathway of the H3 receptor involving receptor modulation of the activity of the serine/threonine-specific protein kinase Akt (protein kinase B, PKB)/GSK-3p (glycogen... 

Non-receptor serine/threonine kinases and dual specificity kinases cAMP-dependent protein kinase (PKA) Phosphoinositol-3-kinase (PI-3K) Cyclin-dependent kinase (CDK) Mitogen-activated protein kinase (MAPK) MAPKK (ERK)... 

The TGF- Ss exert their biological actions by binding to specific receptors, of which there are three types (I, II and III). All are transmembrane glycoproteins. All three TGF-)Ss bind to all three receptor types, although they bind with higher affinity to types I and II receptors (53 kDa and 65 kDa, respectively). The intracellular domains of the type I and II receptors display endogenous serine/threonine protein kinase activity. 

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