====== Protein kinase C ======


[[Protein kinase]] C also known as PKC (EC 2.7.11.13) is a family of protein kinase enzymes that are involved in controlling the function of other proteins through the [[phosphorylation]] of hydroxyl groups of [[serine]] and [[threonine]] amino acid residues on these proteins. PKC enzymes in turn are activated by signals such as increases in the concentration of diacylglycerol (DAG) or calcium ions (Ca2+). Hence PKC enzymes play important roles in several signal transduction cascades.

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The PKC family consists of fifteen isozymes in humans.

They are divided into three subfamilies, based on their second messenger requirements: conventional (or classical), novel, and atypical.

Conventional (c)PKCs contain the isoforms α, βI, βII, and γ. These require Ca2+, DAG, and a phospholipid such as phosphatidylserine for activation. Novel (n)PKCs include the δ, ε, η, and θ isoforms, and require DAG, but do not require Ca2+ for activation. Thus, conventional and novel PKCs are activated through the same signal transduction pathway as phospholipase C. On the other hand, atypical (a)PKCs (including protein kinase Mζ and ι / λ isoforms) require neither Ca2+ nor diacylglycerol for activation. The term "protein kinase C" usually refers to the entire family of isoforms.