CerK (ceramide kinase) produces ceramide 1-phosphate, a sphingophospholipid with recognized signalling properties. It localizes to the Golgi complex and fractionates essentially between detergent-soluble and -insoluble fractions; however, the determinants are unknown. Here, we made a detailed mutagenesis study of the N-terminal PH domain (pleckstrin homology domain) of CerK, based on modelling, and identified key positively charged amino acid residues within an unusual motif in the loop interconnecting beta-strands 6 and 7. These residues are critical for CerK membrane association and polyphosphoinositide binding and activity. Their mutagenesis results in increased thermolability, sensitivity to proteolysis, reduced apparent molecular mass as well as propensity of the recombinant mutant protein to aggregate, indicating that this loop impacts the overall conformation of the CerK protein. This is in contrast with most PH domains whose function strongly relies on charges located in the beta1-beta2 loop.
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http://dx.doi.org/10.1042/BJ20060316 | DOI Listing |
Structure
January 2025
Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India. Electronic address:
In this issue of Structure, Soteriou et al. use cell biology, in vitro reconstitution approaches, and molecular dynamics (MD) simulations to characterize the membrane association of AKT1. The authors show that the AKT1 pleckstrin homology domain contains two essential and cooperative PI(3,4,5)P-binding sites that enable stable membrane binding of AKT1 in the requisite orientation required for effective downstream signaling.
View Article and Find Full Text PDFNeurobiol Dis
December 2024
National Tsing Hua University, Institute of Molecular and Cellular Biology, Department of Life Science, Hsinchu 30013, Taiwan, ROC. Electronic address:
Kinesin-3 KIF1A (UNC-104 in C. elegans) is the major axonal transporter of synaptic vesicles and mutations in this molecular motor are linked to KIF1A-associated neurological disorders (KAND), encompassing Charcot-Marie-Tooth disease, amyotrophic lateral sclerosis and hereditary spastic paraplegia. UNC-104 binds to lipid bilayers of synaptic vesicles via its C-terminal PH (pleckstrin homology) domain.
View Article and Find Full Text PDFCell Tissue Res
December 2024
Laboratory of Molecular Genetics and Virology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
Pleckstrin homology-like domain, family A, member 1 (PHLDA1), one of the three members of PHLDA (1-3) family, has been reported to be expressed in mammalian cells and tissues and play diverse roles in various biological processes such as apoptosis, pyroptosis, and differentiation. Nevertheless, new roles and mechanisms of PHLDA1 action have come to light, with some needing further clarification. The major aim of the publication is to review proapoptotic or antiapoptotic roles of PHLDA1 in cancer, including ample evidence on PHLDA1 role as a tumor suppressor gene or oncogene and its influence on tumor progression.
View Article and Find Full Text PDFChildren (Basel)
November 2024
Rare Diseases Center, Istituto Dermopatico dell'Immacolata, IDI-IRCCS, 00167 Rome, Italy.
Background: Monoallelic damaging variants in (MIM*612870), encoding the Pleckstrin Homology Domain Interacting Protein, have been associated with a novel neurodevelopmental disorder, also termed Chung-Jansen syndrome (CHUJANS, MIM#617991). Most of the described individuals show developmental delay (DD)/intellectual disability (ID), obesity/overweight, and variable congenital anomalies, so the condition can be considered as an ID-overweight syndrome.
Case Description: We evaluated a child presenting with DD/ID and a craniofacial phenotype reminiscent of a Pitt-Hopkins syndrome (PTHS)-like condition.
Sci Rep
November 2024
Guizhou Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, 550025, Guizhou, China.
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