Endoplasmic reticulum-Golgi intermediate compartment protein 2 (ERGIC2) [5] is a gene located on human chromosome 12p11. It encodes a protein of 377 amino acid residues. ERGIC2 protein is also known as PTX1, CDA14 or Erv41.
The biological function of ERGIC2 protein is unknown, although it was initially identified as a candidate tumor suppressor of prostate cancer, [6] and has been shown to induce cell growth arrest and senescence, to suppress colony formation in soft agar, and to decrease invasive potential of human prostate cancer cell line (PC-3 cells). [7] It is now believed to be a chaperon molecule involved in protein trafficking between the endoplasmic reticulum-Golgi intermediate compartment (ERGIC) and Golgi.
The protein contains two hydrophobic transmembrane domains that help anchoring the molecule on the ER membrane, such that its large luminal domain orients inside the ER lumen and both the N- and C-termini are facing the cytosol. ERGIC2 forms a complex with two other proteins, ERGIC3 and ERGIC32, resulting in a shuttle for protein trafficking between ER and Golgi. [8] It has been shown to interact with a number of proteins, such as beta-amyloid, [9] protein elongation factor 1alpha, [10] and otoferlin. [11] Therefore, it may play an important role in cellular functions besides of being a component of a protein trafficking shuttle. More recently, a variant transcript of ERGIC2 has been reported. [12] It has a deletion of four bases at the junction of exons 8 and 9, resulting a frame-shift mutation after codon #189. The variant transcript encodes a truncated protein of 215 residues, which loses 45% of the luminal domain and the transmembrane domain near the C-terminus. This effectively abrogates its function as a protein transporter. A similar variant is also reported in armadillo. So this is not a random mutation. The function of this truncated protein is unknown.
Activating transcription factor 6, also known as ATF6, is a protein that, in humans, is encoded by the ATF6 gene and is involved in the unfolded protein response.
Cux1 is a homeodomain protein that in humans is encoded by the CUX1 gene.
Protein ERGIC-53 also known as ER-Golgi intermediate compartment 53 kDa protein or lectin mannose-binding 1 is a protein that in humans is encoded by the LMAN1 gene.
Beta-microseminoprotein is a protein that in humans is encoded by the MSMB gene. For historical reasons, the scientific literature may also refer to this protein as Prostate secretory protein 94 (PSP94), microseminoprotein (MSP), microseminoprotein-beta (MSMB), beta-inhibitin, prostatic inhibin peptide (PIP), and inhibitin like material (ILM).
Coatomer subunit alpha is a protein that in humans is encoded by the COPA gene.
Coatomer subunit epsilon is a protein that in humans is encoded by the COPE gene.
Sarcoplasmic/endoplasmic reticulum calcium ATPase 3 is an enzyme that in humans is encoded by the ATP2A3 gene.
Homocysteine-responsive endoplasmic reticulum-resident ubiquitin-like domain member 1 protein is a protein that in humans is encoded by the HERPUD1 gene.
Protein transport protein Sec61 subunit beta is a protein that in humans is encoded by the SEC61B gene.
Protein SEC13 homolog is a protein that in humans is encoded by the SEC13 gene.
Protein transport protein Sec61 subunit alpha isoform 1 is a protein that in humans is encoded by the SEC61A1 gene.
Vesicle-trafficking protein SEC22b is a protein that in humans is encoded by the SEC22B gene.
Rho GTPase-activating protein 32 is a protein that in humans is encoded by the RICS gene. RICS has two known isoforms, RICS that are expressed primarily at neurite growth cones, and at the post synaptic membranes, and PX-RICS which is more widely expressed in the endoplasmic reticulum, Golgi apparatus and endosomes. The only known domain of the RICS is the RhoGAP domain, whilst PX-RICS has an additional Phox homology and SH3 domain.
BET1 homolog is a protein that in humans is encoded by the BET1 gene.
Endoplasmic reticulum resident protein 44 (ERp44) also known as thioredoxin domain-containing protein 4 (TXNDC4) is a protein that in humans is encoded by the ERP44 gene.
RAD50-interacting protein 1 is a protein that in humans is encoded by the RINT1 gene.
Conserved oligomeric Golgi complex subunit 1 is a protein that in humans is encoded by the COG1 gene.
Vesicular integral-membrane protein VIP36 is a protein that in humans is encoded by the LMAN2 gene.
Endoplasmic reticulum-Golgi intermediate compartment protein 3 is a protein that in humans is encoded by the ERGIC3 gene. It has been reported to be regulated by micro RNAs and may be important in a cancer.
Syntaxin 17 is a protein that in humans is encoded by the STX17 gene. In horses a duplication in intron 6 causes progressive graying.