8.A.169.1.1
Inheritance of cortical ER protein 2, ICE2, of 491 aas and 10 - 12 TMSs.  It may be involved in septin rign assembly during yeast budding, but may also play a role in ER and Zn²⁺ homeostasis. ICE2 may also play roles in post-translation targeting of proteins to various membranes including the nuclear membrane. Its copy number (~660) in log phase growth is known (Ghaemmaghami et al. 2003). In addition to ICE2, Spa2p-Shs1p interactions may play an important role in cytokinesis (Mino et al. 1998). Fungal Ice2p is in the same superfamily as SERINCs (Alli-Balogun and Levine 2021). Ice2p is an integral endoplasmic reticulum (ER) membrane protein. Ice2p has also been reported to be involved in an ER metabolic branch-point that regulates the flux of lipid either to be stored in lipid droplets or to be used as membrane components, but it may act as a tether that physically bridges the ER at contact sites with both lipid droplets and the plasma membrane via a long loop on the protein's cytoplasmic face that contains multiple predicted amphipathic helices. Diverse members of the fungal Ice2 family have 10 TMSs, which places the long loop on the exofacial face of Ice2p, where it cannot form inter-organelle bridges. It is a full-length homolog of SERINC (serine incorporator), a family of proteins with 10 TMSs found universally in eukaryotes. SERINCs are potent restriction factors for HIV and other viruses in animals (Alli-Balogun and Levine 2021).