2 CD36 Protein
Human CD36 has a total length of 472 amino acids and a predicted
molecular weight of 53 kd(Abumrad et al., 1993). Due to glycosylation,
the actual molecular weight is 88 kd(Greenwalt et al., 1992). CD36
contains two phosphorylation sites and four palmitoylation sites, which
are distributed at the terminals of NH2 and COOH, respectively. And two
ubiquitination sites are also at the COOH terminal.
CD36 is a membrane protein that is synthesized in the polyribosome, then
transfers to the endoplasmic reticulum and Golgi apparatus for further
processing, finally transported by endosome to the cytomembrane(Glatz et
al., 2016). Under the stimulation of insulin(Samovski et al., 2018) or
contraction(Luiken et al., 2002), it moves to the lipid rafts of the
cell membrane to facilitate LCFA uptake, which may be associated with
activation of PI3K-Akt and AMP kinase (AMPK). CD36 not only locates in
plasma membranes and endosomes, but also distributes on
mitochondrial(Monaco et al., 2015), but its specific function on
mitochondrial remains unclear. CD36 is a double transmembrane protein
which can’t form a channel that allows for fatty acids transferring from
outside to the inside(Pepino et al., 2014). Interestingly, the outer
ring of CD36 contains a large hydrophobic cavity, which provides a
docking site for fatty acids and other hydrophobic ligands(Gomez-Diaz et
al., 2016), facilitating the proximity of hydrophobic ligands to the
cell surface, thus promoting the transportation of fatty acids into the
cell.