Function
Guanylate kinase (GK) catalyzes the transfer of phosphate from GMP to GDP using ATP as a phosphate source. GK is essential for recycling GMP and cGMP. GK also forms a domain in the membrane-associated GK (MAGUK) which functions in mitotic spindle orientation and cell adhesion. There is a single mutation in GK which converts it from an enzyme to a protein-binding GK domain[1]. The GK domain has no catalytic activity. The MAGUK contain PDZ (protein-protein interaction domain), WW (proline-rich interaction domain), SH3 (domain found in signaling pathway proteins) and GK domains.
Structural highlights
The GMP binding site of GK is located between its nucleoside monophosphate-binding domain and the LID domain[2].
