Premium
The leucine 10 residue in the pleckstrin homology domain of ceramide kinase is crucial for its catalytic activity
Author(s) -
Kim Tack-Joong,
Mitsutake Susumu,
Kato Mariko,
Igarashi Yasuyuki
Publication year - 2005
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.06.079
Subject(s) - pleckstrin homology domain , ceramide , chemistry , biochemistry , homology modeling , enzyme , phosphorylation , apoptosis
Ceramide kinase (CERK) converts ceramide (Cer) to ceramide‐1‐phosphate (C1P), a newly recognized bioactive molecule capable of regulating diverse cellular functions. The N‐terminus of the CERK protein encompasses a sequence motif known as a pleckstrin homology (PH) domain. However, little is known regarding the functional roles of this domain in CERK. In this study, we have demonstrated that the PH domain of CERK is essential for its enzyme activity. Using site‐directed mutagenesis, we have further determined that Leu10 in the PH domain has an important role in CERK activity. Replacing this residue with a neutral alanine or isoleucine, caused a dramatic decrease in CERK activity to 1% and 29%, respectively, compared to CERK, but had no effect on substrate affinity. The study presented here suggests that the PH domain of CERK is not only indispensable for its activity but also act as a regulator of CERK activity.