RING finger, HC subclass, found in malin and similar proteins
Malin ("mal" for seizure in French), also known as NHL repeat-containing protein 1 (NHLRC1), or EPM2B, is a nuclear E3 ubiquitin-protein ligase that ubiquitinates and promotes the degradation of laforin (EPM2A encoding protein phosphatase). Malin and laforin operate as a functional complex that play key roles in regulating cellular functions such as glycogen metabolism, unfolded cellular stress response, and proteolytic processes. They act as pro-survival factors that negatively regulate the Hipk2-p53 cell death pathway. They also negatively regulate cellular glucose uptake by preventing plasma membrane targeting of glucose transporters. Moreover, they degrade polyglucosan bodies in concert with glycogen debranching enzyme and brain isoform glycogen phosphorylase. Furthermore, they, together with Hsp70, form a new functional complex that suppress the cellular toxicity of misfolded proteins by promoting their degradation through the ubiquitin-proteasome system. Defects in either malin or laforin may cause Lafora disease (LD), a fatal form of teenage-onset autosomal recessive progressive myoclonus epilepsy. In addition, malin may have function, independent of laforin, in lysosomal biogenesis and/or lysosomal glycogen disposal. Malin contains six NHL-repeat protein-protein interaction domains and a C3HC4-type RING-HC finger.
Comment:C3HC4-type RING-HC finger consensus motif: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C, where X is any amino acid and the number of X residues varies in different fingers
Comment:A RING finger typically binds two zinc atoms, with its Cys and/or His side chains in a unique "cross-brace" arrangement.
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