SMIM20

Small integral membrane protein 20 (SMIM20) is a protein that in humans is encoded by the SMIM20 gene.^[5] SMIM20 acts as a prohormone to the peptide hormone phoenixin (PNX) which was discovered for the first time in 2013 in rodent sensory ganglia.^[6] Two alternate cleavage sites within SMIM20 results in two different phoenixin products, Phoenixin-14 (PNX-14) and Phoenixin-20 (PNX-20).^[7]

SMIM20
Identifiers
Aliases	SMIM20, C4orf52, small integral membrane protein 20, MITRAC7, PNX
External IDs	OMIM: 617465; MGI: 1913528; HomoloGene: 82612; GeneCards: SMIM20; OMA:SMIM20 - orthologs
Gene location (Human) Chr. Chromosome 4 (human)[1] Band 4p15.2 Start 25,861,830 bp[1] End 25,929,813 bp[1]
Gene location (Mouse) Chr. Chromosome 5 (mouse)[2] Band 5|5 C1 Start 53,424,425 bp[2] End 53,435,882 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in mucosa of ileum deltoid muscle muscle of leg gastrocnemius muscle tibialis anterior muscle Achilles tendon muscle of thigh quadriceps femoris muscle vastus lateralis muscle biceps brachii Top expressed in right kidney muscle of thigh soleus muscle otolith organ knee joint utricle gastrocnemius muscle masseter muscle quadriceps femoris muscle proximal tubule More reference expression data BioGPS n/a
Gene ontology Molecular function protein binding Cellular component membrane integral component of membrane mitochondrion mitochondrial inner membrane Biological process mitochondrial cytochrome c oxidase assembly Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 389203 66278 Ensembl ENSG00000250317 ENSMUSG00000061461 UniProt Q8N5G0 D3Z7Q2 RefSeq (mRNA) NM_001145432 NM_001394130 NM_001145433 RefSeq (protein) NP_001138904 NP_001138905 Location (UCSC) Chr 4: 25.86 – 25.93 Mb Chr 5: 53.42 – 53.44 Mb PubMed search [3] [4]
Wikidata
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In the study of the evolution of nervous systems, SMIM20 together with NUCB2 have been found to have deep homology across all lineages that preceded creatures with central nervous systems, bilaterians, cnidarians, ctenophores, and sponges as well as in choanoflagellates.^[8][9]

Receptor signaling

Recent studies have found that GPR173, a previously orphaned GPCR, may act as a receptor for PNX-14 and PNX-20.^[10][11][12]

See also

• GPR173