Signal transduction second messenger-independent

The brain contains many other types of second-messenger-independent protein kinases. Examples of other second-messenger-independent protein kinases are listed in Table 23-1. Many of these include enzymes that were identified originally in association with a particular substrate protein but shown later to play a more widespread role in brain signal transduction. The functional role of one of these, [3-adrenergic receptor kinase (PARK), a type of G protein receptor kinase (GRK), is discussed further below. 

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