MIEN1 DNA contains 4 coding exons over 1,63 kb on the minus strand between ERBB2 and GRB7 on human chromosome 17q12. It is also neighbouring mRNA4728.

Transcript (NC_000017.100) length: 1006 bps. Transcription was reported in a variety of cell lines and organs, mainly using gene expression arrays (EMBL-EBI).

None identified.

MIEN1 is a small (12 kDa) membrane bound protein found in a variety of human tumours (Evans et al., 2006). Its main function is to induce cell invasion and it may be involved in metastasis (Dasgupta et al., 2011; Dasgupta and Vishwanatha, 2007; Katz et al., 2010).

MIEN1 is almost exclusively expressed in human tumours, with the notable exception of Leydig cells in testes (Evans et al., 2006).

MIEN1 protein is membrane bound and its stability depends on its localization (our unpublished observations). MIEN1 contains a CVIL amino acid sequence in the C-terminal, which fits the prenylation motif CaaX (Evans et al., 2006). Based on several physical properties, such as size, flexibility, membrane buried preference, and presence of leucine as the X residue, MIEN1 is predicted to be geranylgeranylated in vivo by GGTI enzyme, resulting in the addition of 20-carbon isoprenoid moiety.

The MIEN1 sequence EATYLELASAVKEQYPGIEI conforms to a prototypical immuno-receptor tyrosine-based activation motif (ITAM). ITAMs, such as this of C35 rely on Syk protein kinase for their signaling capacities (Katz et al., 2010). The most commonly reported consequence of MIEN1 over-expression is the induction of cell motility and invasion (Dasgupta et al., 2011; Katz et al., 2010). High levels of MIEN1 expression lead to epithelial to mesenchymal transition in breast cell lines (Katz et al., 2011a). However, intermediate levels lead to a cancer phenomenon rarely observed in experimental models, collective invasion (Katz et al., 2011b).

MIEN1 is very highly conserved among six higher eukaryotic species (identities >77%) but does not seem to have orthologues in microbial organisms (Evans et al., 2006). MIEN1 contains an ITAM motif which is prevalent in immune receptors as well as oncogenic viruses.

A single SNP, rs3809717, was described with no bearing on breast cancer risk (attributed originally to the ERBB2 gene, (Einarsdóttir et al., 2006)).