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Publication Abstract from PubMed

The bifunctional hexokinase KlHxk1 is a key component of glucose dependent signal transduction in Kluyveromyces lactis. KlHxk1 is phosphorylated in vivo and undergoes ATP-dependent autophosphorylation-inactivation in vitro. This study identifies serine-15 as the site of in vivo phosphorylation and serine-157 as the autophosphorylation-inactivation site. X-ray crystallography of the in vivo phosphorylated enzyme indicates the existence of a ring-shaped symmetrical homodimer carrying two phosphoserine-15 residues. In contrast, small-angle X-ray scattering and equilibrium sedimentation analyses reveal the existence of monomeric phosphoserine-15 KlHxk1 in solution. While phosphorylation at serine-15 and concomitant homodimer dissociation are likely to be involved in glucose signalling, mechanism and putative physiological significance of KlHxk1 inactivation by autophosphorylation at serine-157 remain to be established.

In vivo phosphorylation and in vitro autophosphorylation-inactivation of Kluyveromyces lactis hexokinase KlHxk1.,Kettner K, Kuettner EB, Otto A, Lilie H, Golbik RP, Strater N, Kriegel TM Biochem Biophys Res Commun. 2013 Apr 10. pii: S0006-291X(13)00600-1. doi:, 10.1016/j.bbrc.2013.03.121. PMID:23583397^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.