A point mutant of human sphingosine kinase 1 with increased catalytic activity

FEBS Letters

M. Pitson, Stuart¹  Zebol, Julia R.¹  Wattenberg, Binks W.¹  D'Andrea, Richard J.¹  Moretti, Paul A.B.¹  Vadas, Mathew A.¹ 

[1] Hanson Centre for Cancer Research, Division of Human Immunology, Institute of Medical and Veterinary Science, Frome Road, Adelaide, SA 5000, Australia

关键词: Sphingosine kinase;    Enzyme catalysis;    Sphingosine 1-phosphate;    Lipid kinase;    SK;    sphingosine kinase;    S1P;    sphingosine 1-phosphate;    hSK;    human SK1;    DGK;    diacylglycerol kinase;    hSKWT;    wild-type hSK;    hSKG113D;    hSK with Gly113→Asp mutation;    hSKG113A;    hSK with Gly113→Ala mutation;    PMA;    phorbol 12-myristate 13-acetate;    TNFα;    tumour necrosis factor-α;   

DOI  :  10.1016/S0014-5793(01)03162-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Sphingosine kinase (SK) catalyses the formation of sphingosine 1-phosphate, a lipid second messenger that has been implicated in mediating such fundamental biological processes as cell growth and survival. Very little is currently known regarding the structure or mechanisms of catalysis and activation of SK. Here we have tested the functional importance of Gly¹¹³, a highly conserved residue of human sphingosine kinase 1 (hSK), by site-directed mutagenesis. Surprisingly, a Gly¹¹³→Ala substitution generated a mutant that had 1.7-fold greater catalytic activity than wild-type hSK (hSK^WT). Our data suggests that the Gly¹¹³→Ala mutation increases catalytic efficiency of hSK, probably by inducing a conformational change that increases the efficiency of phosphoryl transfer. Interestingly, hSK^G113A activity could be stimulated in HEK293T cells by cell agonists to a comparable extent to hSK^WT.

【 授权许可】

Unknown