2',3'-Cyclic-nucleotide 3'-phosphodiesterase
Template:Short description Template:Cs1 config Template:Infobox enzyme Template:Infobox gene 2′,3′-Cyclic-nucleotide 3'-phosphodiesterase (EC 3.1.4.37, CNPase, systematic name nucleoside-2′,3′-cyclic-phosphate 2′-nucleotidohydrolase) is an enzyme that in humans is encoded by the CNP gene.[1][2]
Reaction
CNPase catalyzes the following reaction:
- nucleoside 2′,3′-cyclic phosphate + H2O nucleoside 2′-phosphate
Function
CNPase is a myelin-associated enzyme that makes up 4% of total CNS myelin protein, and is thought to undergo significant age-associated changes.[3] It is named for its ability to catalyze the phosphodiester hydrolysis of 2',3'-cyclic nucleotides to 2'-nucleotides, though a cohesive understanding of its specific physiologic functions are still ambiguous.[4]
Structural studies have revealed that four classes of CNPases belong to one protein superfamily. CNPase's catalytic core consists of three alpha-helices and nine beta-strands. The proposed mechanism of CNPases phosphodiesterase catalytic activity is similar to the second step of the reaction mechanism for RNase A.[5]
CNPase is expressed exclusively by oligodendrocytes in the CNS, and the appearance of CNPase seems to be one of the earliest events of oligodendrocyte differentiation.[6] CNPase is thought to play a critical role in the events leading up to myelination.[7]
CNPase also associates with microtubules in brain tissue and FRTL-5 thyroid cells, and is reported to have microtubule-associated protein-like activity (MAP; see MAP2), being able to catalyze microtubule formation at low molar ratios. Deletion of the C-terminus of CNPase or phosphorylation abolish the catalytic activity of microtubule formation. CNPase can link tubulin to cellular membranes, and might be involved in the regulation cytoplasmic microtubule distribution.[8]
CNPase has also been demonstrated to inhibit the replication of HIV-1 and other primate lentiviruses by binding the retroviral Gag protein and inhibiting the genesis of nascent viral particles. Whether this is a biological function of CNPase or a coincidental activity remains unclear.[9] Template:Clear
References
External links
Further reading
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