C-Jun-amino-terminal kinase-interacting protein 4; JIP-4; JNK-interacting protein 4; cancer/testis antigen 89; CT89; human lung cancer oncogene 6 protein; HLC-6; JNK-associated leucine-zipper protein; JLP; mitogen-activated protein kinase 8-interacting protein 4; proliferation-inducing protein 6; protein highly expressed in testis; PHET; sperm surface protein; sperm-associated antigen 9; sperm-specific protein; Sunday driver 1 (SPAG9, HSS, KIAA0516, MAPK8IP4, SYD1, HLC6)

Function

• the JNK-interacting protein (JIP) group of scaffold proteins selectively mediate JNK signaling by aggregating specific components of the MAPK cascade to form a functional JNK signaling module
• interacts with MAX, MAPK8, MAPK9, MAPK10,MAPK14, MAP3K3, MYC, KNS2, MAP2K4
• interaction with KNS2 is important in the formation of ternary complex with MAPK8
• interacts with NFKB1
• phosphorylated by MAPK8 & MAPK14
• phosphorylated upon DNA damage, probably by ATM or ATR

Structure

• homo-oligomer
• belongs to the JIP scaffold family

Compartment

• cytoplasm
• perinuclear distribution in response to stress signals such as UV radiation
• isoform 5:
  • cytoplasmic vesicle, secretory vesicle, acrosome
  • associated with the plasma membrane of the acrosome
  • also localizes in the acrosome matrix

Alternative splicing

named isoforms=8

Expression

• isoform 5 is expressed only in testis
  • expressed in round spermatids of stages 1-3
  • absent in spermatogonia & spermatocytes
• isoform 3
  • expressed only in testis
  • expression is increased in systemic sclerosis fibroblasts
• isoform 4 is expressed in testis & in acute myeloid leukemia

More general terms

• JNK-interacting protein
• phosphoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=9043
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:9043
• OMIM: https://mirror.omim.org/entry/605430
• UniProt: http://www.uniprot.org/uniprot/O60271.html