Characterisation of the cell-surface localised palmitoyl acyl transferase, DHHC5
type: CreativeWork
description: S-Palmitoylation is the reversible addition of 16-carbon fatty acids onto cysteine residues of proteins. The functional consequences of palmitoylation are diverse and it has been demonstrated to play a critical role in several physiological and disease pathways. DHHC palmitoyl acyl transferase (DHHC-PAT) enzymes are responsible for catalysing the addition of acyl groups onto cysteine residues and there are 23 human DHHC-PAT isoforms. All isoforms share a conserved DHHC catalytic motif and they display heterogeneity in their N- and C- termini. This coupled with differing sub-cellular localisations is thought to be the basis of substrate specificity. DHHC5 is a cell surface localised DHHC-PAT which has a characteristic, long cytoplasmic C-tail which is responsible for substrate recruitment. DHHC5 has an established role in hippocampal learning and memory formation. It is also known to palmitoylate phospholemman (PLM), thereby regulating cardiac sodium pump activity. However, the regulatory mechanisms governing substrate recruitment by DHHC5 are not understood and it is thought that there are more, currently unidentified DHHC5 substrates. The aims of this project were to i) identify the PLM binding site on the DHHC5 C-tail and investigate how PLM recruitment to DHHC5 is regulated, and ii) develop and use a peptide-based array to identify novel DHHC5 substrates. A small peptide-based array identified a PLM binding site on the DHHC5 C-tail, positioned just after the final transmembrane domain. Further interrogation of this region revealed that DHHC5 is palmitoylated on its C-tail at a di-cysteine motif situated close to the PLM binding site at residues 236/237. Over-expression of DHHC20 increased palmitoylation of DHHC5 in HEK293 cells, but not when the di-cysteine motif was mutated. DHHC20 overexpression in HEK293 cells also increased coimmunoprecipitation of PLM with DHHC5 and again the di-cysteine motif was required for this. Therefore, it was concluded that DHHC20 pa…
abstract: S-Palmitoylation is the reversible addition of 16-carbon fatty acids onto cysteine residues of proteins. The functional consequences of palmitoylation are diverse and it has been demonstrated to play a critical role in several physiological and disease pathways. DHHC palmitoyl acyl transferase (DHHC-PAT) enzymes are responsible for catalysing the addition of acyl groups onto cysteine residues and there are 23 human DHHC-PAT isoforms. All isoforms share a conserved DHHC catalytic motif and they display heterogeneity in their N- and C- termini. This coupled with differing sub-cellular localisations is thought to be the basis of substrate specificity. DHHC5 is a cell surface localised DHHC-PAT which has a characteristic, long cytoplasmic C-tail which is responsible for substrate recruitment. DHHC5 has an established role in hippocampal learning and memory formation. It is also known to palmitoylate phospholemman (PLM), thereby regulating cardiac sodium pump activity. However, the regulatory mechanisms governing substrate recruitment by DHHC5 are not understood and it is thought that there are more, currently unidentified DHHC5 substrates. The aims of this project were to i) identify the PLM binding site on the DHHC5 C-tail and investigate how PLM recruitment to DHHC5 is regulated, and ii) develop and use a peptide-based array to identify novel DHHC5 substrates. A small peptide-based array identified a PLM binding site on the DHHC5 C-tail, positioned just after the final transmembrane domain. Further interrogation of this region revealed that DHHC5 is palmitoylated on its C-tail at a di-cysteine motif situated close to the PLM binding site at residues 236/237. Over-expression of DHHC20 increased palmitoylation of DHHC5 in HEK293 cells, but not when the di-cysteine motif was mutated. DHHC20 overexpression in HEK293 cells also increased coimmunoprecipitation of PLM with DHHC5 and again the di-cysteine motif was required for this. Therefore, it was concluded that DHHC20 pa…
author: Plain, Fiona
language: eng
date published: 2018
date modified: 2026-07-24T02:08:39Z
provider: University of Dundee
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Dundee