plexin-B1; Semaphorin receptor SEP (PLXNB1 KIAA0407 PLXN5 SEP)

Function

• binds
  • semaphorin 4D: binding
    • promotes binding of cytoplasmic ligands
  • plexin A1
  • Rho guanine nucleotide exchange factor 11 (ARHGEF11)
  • Rho guanine nucleotide exchange factor 12 (ARHGEF12)
  • erb B2
  • c-met protein
  • macrophage stimulating 1 receptor (MST1R)
  • rho6 protein (RND1)
  • neuropilin 1 (NRP1)
  • neuropilin 2 (NRP2)
  • RAC1 that has been activated by GTP binding
• phosphorylated (after semaphorin 4D binding) by
  • erb B2
  • c-met protein
• rhoA activation
• changes of the actin cytoskeleton
• axon guidance
• invasive growth and cell migration

Structure

• monomer, & heterodimer with PLXNB2 after proteolytic processing
• proteolytic processing favors heterodimerization with PLXNB2 & SEMA4D binding
• belongs to the plexin family
• contains 3 IPT/TIG domains
• contains 1 Sema domain

Compartment

• isoform 1: cell membrane
• isoforms 2,3: secreted

Alternative splicing

named isoforms=3

Expression

• high expression in fetal kidney
• lower expression in fetal brain, lung liver

Pathology

• overexpressed & constitutively Tyr phosphorylated in carcinoma cell lines
  • colon carcinoma
  • hepatocellular carcinoma
  • pancreatic carcinoma
  • gastric carcinoma
• promotion of invasive growth from overexpression & c-MET activation

More general terms

• plexin B

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:5364
• OMIM: https://mirror.omim.org/entry/601053
• UniProt: http://www.uniprot.org/uniprot/O43157.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=5364