MAPK8IP1

This gene encodes a regulator of the pancreatic beta-cell function. It is highly similar to JIP-1, a mouse protein known to be a regulator of c-Jun amino-terminal kinase (Mapk8). This protein has been shown to prevent MAPK8 mediated activation of transcription factors, and to decrease IL-1 beta and MAP kinase kinase 1 (MEKK1) induced apoptosis in pancreatic beta cells. This protein also functions as a DNA-binding transactivator of the glucose transporter GLUT2. RE1-silencing transcription factor (REST) is reported to repress the expression of this gene in insulin-secreting beta cells. This gene is found to be mutated in a type 2 diabetes family, and thus is thought to be a susceptibility gene for type 2 diabetes.

MITOGEN-ACTIVATED PROTEIN KINASE 8 INTERACTING PROTEIN 1

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. Required for JNK activation in response to excitotoxic stress. Cytoplasmic MAPK8IP1 causes inhibition of JNK-regulated activity by retaining JNK in the cytoplasm and inhibiting JNK phosphorylation of c-Jun. May also participate in ApoER2-specific reelin signaling. Directly, or indirectly, regulates GLUT2 gene expression and beta-cell function. Appears to have a role in cell signaling in mature and developing nerve terminals. May function as a regulator of vesicle transport, through interactions with the JNK-signaling components and motor proteins. Functions as an anti-apoptotic protein and whose level seems to influence the beta-cell death or survival response. Acts as a scaffold protein that coordinates with SH3RF1 in organizing different components of the JNK pathway, including RAC1 or RAC2, MAP3K11/MLK3 or MAP3K7/TAK1, MAP2K7/MKK7, MAPK8/JNK1 and/or MAPK9/JNK2 into a functional multiprotein complex to ensure the effective activation of the JNK signaling pathway. Regulates the activation of MAPK8/JNK1 and differentiation of CD8(+) T-cells.

JUN phosphorylationIEA:Ensembl
Negative regulation of intrinsic apoptotic signaling pathwayIEA:Ensembl
Negative regulation of JUN kinase activityISS:UniProtKB
Positive regulation of JNK cascadeISS:UniProtKB
Regulation of CD8-positive, alpha-beta T cell proliferationISS:UniProtKB
Regulation of JNK cascadeISS:UniProtKB
Regulation of transcription, DNA-templatedIEA:Ensembl
Vesicle-mediated transportISS:UniProtKB

Cytoplasm
Cytoplasm, perinuclear region
Nucleus
Endoplasmic reticulum membrane
Mitochondrion membrane
Accumulates in cell surface projections. Under certain stress conditions, translocates to the perinuclear region of neurons. In insulin-secreting cells, detected in both the cytoplasm and nucleus (By similarity).

Diabetes mellitus, non-insulin-dependent (NIDDM):
A multifactorial disorder of glucose homeostasis caused by a lack of sensitivity to the body's own insulin. Affected individuals usually have an obese body habitus and manifestations of a metabolic syndrome characterized by diabetes, insulin resistance, hypertension and hypertriglyceridemia. The disease results in long-term complications that affect the eyes, kidneys, nerves, and blood vessels.

Phosphorylated by MAPK8, MAPK9 and MAPK10. Phosphorylation on Thr-103 is also necessary for the dissociation and activation of MAP3K12. Phosphorylated by isoform 1 and isoform 2 of VRK2. Hyperphosphorylated during mitosis following activation of stress-activated and MAP kinases.
Ubiquitinated. Two preliminary events are required to prime for ubiquitination; phosphorylation and an increased in intracellular calcium concentration. Then, the calcium influx initiates ubiquitination and degradation by the ubiquitin-proteasome pathway.