PIK3R1 Back

phosphoinositide-3-kinase, regulatory subunit 1 (alpha)

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NCBI Description of PIK3R1

Phosphatidylinositol 3-kinase phosphorylates the inositol ring of phosphatidylinositol at the 3-prime position. The enzyme comprises a 110 kD catalytic subunit and a regulatory subunit of either 85, 55, or 50 kD. This gene encodes the 85 kD regulatory subunit. Phosphatidylinositol 3-kinase plays an important role in the metabolic actions of insulin, and a mutation in this gene has been associated with insulin resistance. Alternative splicing of this gene results in four transcript variants encoding different isoforms.

Community Annotation of PIK3R1 Add / Edit PIK3R1: Annotations

PIK3R1 gene encodes the 85 kD regulatory subunit of phosphatidylinositol 3-kinase (PI3K). The PI3K pathway is a well-described pathway, and activating events in this pathway are thought to be oncogenic. Alternative splicing of this gene results in three transcript variants encoding different isoforms.

Alterations in this gene are commonly observed in many cancer types. It is seen in ~30% of uterine/endometrial cancers, between 5-30% of gastric, prostate, ovarian, GBM, and adenoid cystic cancers, and in 1-5% of breast, head and neck, and lung cancers. In colon cancers, this gene is altered in approximately 4% of cases.

Added by Eli Van Allen


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Figure notes

• "Mouse over" a mutation to see details.
• Missense green saturation indicates evolutionary conservation of the mutated positions.
• Red hashes in protein strip are splice sites.
• Blue-white-red bars are log2 copy ratio distributions (–1 to +1) from Zack et al. (2013).


PIK3R1 is highly significantly mutated in
84 patients (33%)
Glioblastoma multiforme
33 patients (11%)
combined cohort
181 patients (3%)
22 patients (2%)
PIK3R1 is significantly mutated in
PIK3R1 is near significance in
Esophageal adenocarcinoma
6 patients (4%)

Click on a tumor type to see its full list of significant genes.

Data details

Mutation list for PIK3R1