3D mapping of glycogenosis-causing mutations in the large regulatory alpha subunit of phosphorylase kinase

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE

卷:1782

Article

Carriere, Cathelene ; Jonic, Slavica ; Mornon, Jean-Paul ; Callebaut, Isabelle

关键词: Phosphorylase kinase;    Phosphorylase kinase deficiency;    Glycogen storage disease;    X-linked liver Glycogenosis;    Molecular modeling;   

DOI  :  10.1016/j.bbadis.2008.09.011

来源: Elsevier

【 摘 要 】

Mutations in the liver isoform of the Phosphorylase Kinase (PhK) alpha subunit (PHKA2 gene) cause X-linked liver glycogenosis (XLG), the most frequent type of PhK deficiency (glycogen-storage disease type IX). XLG patients can be divided in two subgroups, with similar clinical features but different activity of PhK (decreased in liver and blood cells for XLG-I and low in liver but normal or enhanced in blood cells for XLG-II). Here, we show that the PHKA2 missense mutations and small in-frame deletions/insertions are concentrated into two domains of the protein, which were recently described. In the N-terminal glucoamylase domain, mutations (principally leading to XLG-II) are clustered within the predicted glycoside-binding site, suggesting that they may have a direct impact on a possible hydrolytic activity of the PhK alpha subunit, which remains to be demonstrated. In the C-terminal calcineurin B-like domain (domain D), mutations (principally leading to XLG-I) are clustered in a region predicted to interact with the regulatory region of the PhK catalytic subunit and in a region covering this interaction site. Altogether, these results show that PHKA2 missense mutations or small in-frame deletions/insertions may have a direct impact on the PhK alpha functions and provide a framework for further experimental investigation. (c) 2008 Elsevier B.V. All rights reserved.

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