gephyrin; includes: molybdopterin adenylyltransferase, MPT adenylyltransferase, domain G; molybdopterin molybdenumtransferase; MPT Mo-transferase; domain E (GPHN, GPH, KIAA1385)

Function

• microtubule-associated protein
• involved in membrane protein-cytoskeleton interactions
• thought to anchor the inhibitory glycine receptor (GLYR) to subsynaptic microtubules
• catalyzes 2 steps in the biosynthesis of the molybdenum cofactor
• in the 1st step, molybdopterin is adenylated
• subsequently, molybdate is inserted into adenylated molybdopterin & AMP is released

molybdopterin + ATP <--> adenylyl-molybdopterin + diphosphate

adenylyl-molybdopterin + molybdate
                 <-->
molybdenum-cofactor + adenylate

• inhibited by copper & tungsten
• cofactor biosynthesis; molybdopterin biosynthesis
• interacts with GABARAP (putative)

Cofactor: Mg+2 (putative)

Structure

• homotrimer
• in the N-terminal section; belongs to the moaB/mog family
• In the C-terminal section; belongs to the moeA family

Compartment

• cell junction, synapse (putative)
• cell junction, synapse, postsynaptic cell membrane
• peripheral membrane protein; cytoplasmic side (putative)
• cytoplasm, cytoskeleton (putative)
• cytoplasmic face of glycinergic postsynaptic membranes (putative)

Alternative splicing

named isoforms=2

Pathology

• defects in GPHN are the cause of molybdenum cofactor deficiency type C
• defects in GPHN are a cause of startle disease

More general terms

• microtubule-associated protein (MAP)
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=10243
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:10243
• OMIM: https://mirror.omim.org/entry/149400
• OMIM: https://mirror.omim.org/entry/252150
• OMIM: https://mirror.omim.org/entry/603930
• UniProt: http://www.uniprot.org/uniprot/Q9NQX3.html