SPAG9

Function

The JNK-interacting protein (JIP) group of scaffold proteins selectively mediates JNK signaling by aggregating specific components of the MAPK cascade to form a functional JNK signaling module (PubMed:14743216). Regulates lysosomal positioning by acting as an adapter protein which links PIP4P1-positive lysosomes to the dynein-dynactin complex (PubMed:29146937). Assists PIKFYVE selective functionality in microtubule-based endosome-to-TGN trafficking (By similarity).

Post-translational modifications

Phosphorylated by MAPK8 and MAPK14.

Sequence Similarities

Belongs to the JIP scaffold family.

Tissue Specificity

Expressed only in testis on the round spermatids of stage I, II and II. Absent in spermatogonia and spermatocyte.

Isoform 4

Expressed in testis and in acute myeloid leukemia (AML) patients.

Isoform 3

Expressed in testis.

Cellular localization

• Cytoplasm
• Cytoplasm
• Perinuclear region
• Lysosome membrane
• 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 acrosomal compartment and also localizes in the acrosome matrix.

Alternative names

HSS, KIAA0516, MAPK8IP4, SYD1, HLC6, SPAG9, C-Jun-amino-terminal kinase-interacting protein 4, JIP-4, JNK-interacting protein 4, Cancer/testis antigen 89, Human lung cancer oncogene 6 protein, JNK-associated leucine-zipper protein, Mitogen-activated protein kinase 8-interacting protein 4, Proliferation-inducing protein 6, Protein highly expressed in testis, Sperm surface protein, Sperm-associated antigen 9, Sperm-specific protein, Sunday driver 1, CT89, HLC-6, JLP, PHET

Database links

swissprot:O60271 omim:605430 entrezGene:9043

Other research areas

• Neuroscience