9.B.37 The Huntington-interacting Protein 14 (HIP14) Family
The Huntington-interacting protein 14 (HIP14) is reported to be a palmitoyltransferase required for exocytosis and targeting of the palmitoylated cysteine string protein (CSP) and the SNAP25 protein which are mislocalized in a HIP14 mutant (Ohyama et al., 2007). HIP14 also palmitoylates CSP. HIP14 may be necessary for presynaptic function including neurotransmitter release by regulating the trafficking of CSP to synapses (Ducker et al., 2004; Ohyama et al., 2007; Stowers and Isacoff, 2007; Yanai et al., 2006).
HIP14 is reported to be a divalent cation transporter capable of transporting Mg2+ found only in eukaryotes (Quamme, 2009). It has up to eight N-terminal Ankyrin repeats (residues 25-270) followed by the transmembrane domain (residues 300-560; The zfDHHC domain superfamily). As of 2018, the function of this protein as a Mg2+ transporter was under debate (Schäffers et al. 2018).
The reaction proposed for HIP14 is:
M2+(in) ⇌ M2+(out)