1.A.64 The Plasmolipin (Plasmolipin) Family
Plasmolipin (PLLP) is an 18-kDa proteolipid or lipoprotein found in kidney and brain, where it is restricted to the apical surface of tubular epithelial cells and to mammalian myelinated tracts, respectively. This protein is made during sciatic nerve development and regeneration in the rat. It has 182 aas and 4 TMSs (Fischer and Sapirstein, 1994). Addition of plasmolipin to lipid bilayers induces the formation of ion channels, which are voltage-dependent and K+-selective (Tosteson and Sapirstein, 1981). PLLP functions in myelin biogenesis through organization of myelin liquid-ordered membranes in the Golgi complex (Yaffe et al. 2015).
Plasmolipin has many homologues. These are referred to as CKLF-like MARVEL transmembrane domain containing protein, chemokine-like factor and T-cell differentiation marker (Mitsugumin and Synaptogyrin). Most are about 180 residues, but several are about twice as large with 8 TMSs and an internal repeat (e.g., the myeloid-associated differentiation marker of humans (MAL or MYADM; Q96S97) or the rat (EAL84950). Synthesis of these proteins are induced by retinoic acid (Cui et al., 2001).
Plasmolipin localizes to and recycles between the plasma membrane and the Golgi complex. In the Golgi complex, it forms oligomers which block Golgi to plasma membrane transport of the secretory vesicular stomatitis virus G protein (VSVG) (Yaffe et al. 2015).
The transport reaction that occurs with plasmolipin in artificial membranes is:
Ions (in) Ions (out)