PIN1 — Peptidyl-prolyl cis-trans Isomerase NIMA-Interacting 1

Gene Overview

flowchart TD
    PIN1["PIN1"] -->|"modulates"| TRIM32["TRIM32"]
    PIN1["PIN1"] -->|"phosphorylates"| TRIM32["TRIM32"]
    PIN1["PIN1"] -->|"binds"| SUMO2_3["SUMO2/3"]
    PIN1["PIN1"] -->|"binds"| SENP1["SENP1"]
    PIN1["PIN1"] -->|"phosphorylates"| ANXA2["ANXA2"]
    PIN1["PIN1"] -->|"associated with"| Alzheimer_s_disease["Alzheimer's disease"]
    PIN1["PIN1"] -->|"regulates"| Aging["Aging"]
    PIN1["PIN1"] -->|"regulates"| Neurodegeneration["Neurodegeneration"]
    PIN1["PIN1"] -->|"regulates"| Als["Als"]
    PIN1["PIN1"] -->|"regulates"| Cancer["Cancer"]
    PIN1["PIN1"] -->|"regulates"| Longevity["Longevity"]
    PIN1["PIN1"] -->|"regulates"| Ms["Ms"]
    PIN1["PIN1"] -->|"regulates"| Tumor["Tumor"]
    PIN1["PIN1"] -->|"treats"| Tumor["Tumor"]
    style PIN1 fill:#4fc3f7,stroke:#333,color:#000

PIN1 (Peptidyl-prolyl cis-trans Isomerase NIMA-Interacting 1) is a peptidyl-prolyl cis-trans isomerase that specifically binds to phosphorylated serine/threonine-proline motifs and catalyzes the isomerization of peptide bonds. PIN1 is a critical regulator of protein function in multiple signaling pathways and has been implicated in Alzheimer’s disease, Parkinson’s disease, and other neurodegenerative conditions.

Gene Information

Function

PIN1 is a unique peptidyl-prolyl cis-trans isomerase (PPIase) that catalyzes the isomerization of peptide bonds preceding phosphorylated serine or threonine residues. This post-translational modification can dramatically alter protein conformation and function.

Structural Features

• WW Domain: N-terminal domain that recognizes phosphorylated serine/threonine-proline motifs

• PPIase Domain: C-terminal catalytic domain that catalyzes cis-trans isomerization

• Substrate Specificity: Highly specific for pSer/Thr-Pro motifs, unique among PPIases

Biological Functions

1. Tau Phosphorylation Regulation: PIN1 binds to phosphorylated tau (p-tau) and promotes proper tau folding, preventing aggregation

2. Cell Cycle Regulation: Controls entry and progression through mitosis via regulation of mitotic proteins

3. Signal Transduction: Modulates signaling pathways including MAPK, PI3K/AKT, and Wnt/β-catenin

4. Transcriptional Regulation: Influences transcription factor activity including p53, c-Jun, and NF-κB

5. Protein Quality Control: Aids in proper folding and trafficking of proteins

Disease Associations

Alzheimer’s Disease

PIN1 plays a complex role in AD pathophysiology:

• Beneficial Function: Catalyzes isomerization of phosphorylated tau, promoting proper tau function

• Pathogenic Dysfunction: In AD brain, PIN1 activity is reduced, leading to tau hyperphosphorylation and neurofibrillary tangle formation

• Therapeutic Target: PIN1 activators are being explored as potential AD therapeutics

• Reference: Lu et al., Science (1999)

Parkinson’s Disease

• PIN1 levels are altered in PD brains

• May regulate α-synuclein phosphorylation and aggregation

• Reference: Sala et al., J. Neurochem. (2009)

Cancer

• Overexpression in multiple cancers including breast, prostate, and lung

• Promotes cell proliferation and survival

• Reference: Lu et al., Nat. Rev. Cancer (2009)

Expression

Brain Expression

• Cerebral Cortex: Moderate to high expression, particularly in pyramidal neurons

• Hippocampus: High expression in CA1-CA3 regions and dentate gyrus

• Substantia Nigra: Present in dopaminergic neurons

• Cerebellum: Moderate expression in Purkinje cells

Cellular Localization

• Nuclear: Predominantly nuclear localization

• Cytoplasmic: Also present in cytoplasm

• Neuronal Processes: Localizes to dendritic spines

Common Variants

Therapeutic Implications

Drug Development

• PIN1 Activators: Pharmaceutical compounds that enhance PIN1 activity for AD treatment

• PIN1 Inhibitors: Being developed for cancer therapy

• Reference: Pastorino et al., Nat. Rev. Drug Discov. (2016)

Biomarker Potential

• PIN1 expression in CSF may serve as a biomarker for neurodegeneration

• Reference: Matsuda et al., J. Alzheimers Dis. (2015)

See Also

• Tau Pathology

• Protein Phosphorylation

• Alzheimer’s Disease Genes

• GSK3B - Tau kinase

• CDK5 - Tau kinase

• PP2A - Tau phosphatase