Control of protein palmitoylation by regulating substrate recruitment to a zDHHC-protein acyltransferase

Abstract

Although palmitoylation regulates numerous cellular processes, as yet efforts to manipulate this post-translational modification for therapeutic gain have proved unsuccessful. The Napump accessory sub-unit phospholemman (PLM) is palmitoylated by zDHHC5. Here, we show that PLM palmitoylation is facilitated by recruitment of the Na-pump α sub-unit to a specific site on zDHHC5 that contains a juxtamembrane amphipathic helix. Site-specific palmitoylation and GlcNAcylation of this helix increased binding between the Na-pump and zDHHC5, promoting PLM palmitoylation. In contrast, disruption of the zDHHC5-Na-pump interaction with a cell penetrating peptide reduced PLM palmitoylation. Our results suggest that by manipulating the recruitment of specific substrates to particular zDHHC-palmitoyl acyl transferases, the palmitoylation status of individual proteins can be selectively altered, thus opening the door to the development of molecular modulators of protein palmitoylation for the treatment of disease.

Disposition of Proteins and Lipids in Synaptic Membrane Compartments Is Altered in Q175/Q7 Huntington’s Disease Mouse Striatum

“…Thus, palmitoylation catalyzed by the Huntingtin interactor proteins HIP14 (zDHHC17) or HIP14L (zDHHC13) may account for the biochemical redistribution we observe. In fact, palmitoylation has been reported for vGlut1 ( Zareba-Koziol et al, 2018 ), Na + /K + ATPase ( Plain et al, 2020 ), and GLUT3 ( Stapel et al, 2019 ), AMPAR and GABAR ( Zareba-Koziol et al, 2018 ).…”

Substrate recruitment by zDHHC protein acyltransferases

“…In addition to the catalytic cysteine residue of the zDHHC motif that forms the acyl-enzyme intermediate, palmitoylation of cysteines C-terminal to the DHHC-CRD has been detected [ 47 , 97 ] and shown to be functionally important [ 47 , 53 ]. Although It was proposed that palmitoylation might be an intramolecular event, in which palmitate transfers from the DHHC cysteine to cysteines outside the CRD [ 97 ], or a homologous intermolecular transfer, there is strong evidence in at least two cases, a zDHHC PAT is palmitoylated by another [ 98 , 99 ].…”

“…zDHHC20 was identified as the likely upstream PAT using a proximity biotinylation approach and confirmed by a demonstration that coexpression with zDHHC5 increased its palmitoylation. Palmitoylation of the cysteine cluster in zDHHC5 is necessary for association with its substrates, Golga7b [ 53 ] and the Na-pump [ 99 ]. This facilitation of substrate recruitment would manifest as increased PAT activity.…”

“…The zDHHC structures revealed that the enzyme active site is located at the interface of the membrane and cytoplasm, appropriately positioned to modify membrane-proximal cysteines [ 14 ]. How substrate interactions with domains of the zDHHC protein that are distant from the active-site facilitate catalysis is an open question, but one that is beginning to be addressed [ 99 ]. As noted previously, the C-terminal PaCCT motif in zDHHC5 includes the palmitoylated cysteines and forms a juxtamembrane amphipathic α-helix.…”

Tetraspanins as Potential Therapeutic Candidates for Targeting Flaviviruses

“…CD151 palmitoylation has been reported to play significant function in assembly of the large network of cell surface tetraspanin-protein interactions, distribution in tetra-CD151 showed markedly diminished stability during biosynthesis. Disruption of tetraspanin domain through palmitoylation dynamics may therefore represent a candidate therapeutic strategy to combat viral infections (104). The siRNAmediated knockdown of tetraspanin CD151 or antibodymediated blocking of CD81 was shown to reduce virus entry/internalization.…”