Camp -dependent protein kinase of mitochondria structurk and possible role of the substrates

A cAMP dependent protein kinase has been shown to be associated to the inner membrane of mammalian mitochondria -4Technikova-Dobrova et al. FEBS Lett. 1994, 350,187). The active site cf the catalytic subur.it is located at the matrix s ids [ Sardanel 1 i et al. FEBS Lett. 1996, 396, 276], the regulatory subuiut apparently interacts with the cytosoi ic cAKP. The mitochondrial PKA phosphorylates a number oi proteins present in the matrix or associated to the inner membrane. One of the membrane associated prot ein is the nuclear encoded 18 kDa (IPS AQDQ... Subunit of NADH-ubiquinone oxidoreductrtse (ccrr.plGx 11 r,f the resp iratory chain :?apa et al. FEBS L,ett . 1996, 379,299J. A 42 kUa prctein, phosphorylated cy the mitocncndria1 PKA, is loosely associâted to the three complexes of the respiratory chain as well as to the ATP synthase. Another protein phosphorylated by the mitochondrial ?KA has ".W. cf 5.5 kDa and does not belong to the complexes of the ox idat ive phosphorylaticn. The mitochondrial PKA, which would represent another siqnal 1 ing pathway for' cAMP, might have a role in the physio1ogica1 control of mitochondrial function and biogenesis.