Table I.
Summary of the physiological function and associated signaling pathways of the 25 proteins studied.
| Protein | Description/full name | Main function | References |
|---|---|---|---|
| TSC1 | Tuberous sclerosis 1 | Tumor suppressor; stimulates specific GTPases | (13) |
| EGFR | Epidermal growth factor receptor | Activates PI3K, which activates Akt (promotes cell survival and proliferation) | (14) |
| MERTK | MER proto oncogene tyrosine kinase | Tyrosine kinase receptor with oncogenic properties that is often overexpressed or activated in various types of malignancy; member of the MER/AXL/TYRO3 receptor kinase family; regulates melanoma cell migration and survival | (15,16) |
| RHEB | Ras homolog enriched in brain | Regulates growth and cell cycle progression via the insulin/TOR/S6K signaling pathway | (17) |
| RPS6KB1 | Ribosomal protein S6 β1 | mTOR downstream protein; promotes protein synthesis, cell growth, and cell proliferation | (18) |
| CCND1 | Cyclin D1 | Functions as a regulatory subunit of cyclin-dependent kinase (CDK)4 or CDK6, whose activity is required for cell cycle G1/S transition | (19) |
| TP53 | Tumor protein p53 | Tumor suppressor; induces cell cycle arrest, apoptosis, senescence, DNA repair or changes in metabolism | (20) |
| PTEN | Phosphatase and tensin homolog | Tumor suppressor; mostly mutated in a large number of cancers | (21,22) |
| PIK3CA | Phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α | Belongs to the PI3K family; has roles in various signaling pathways; involved in proliferation, oncogenic transformation, cell survival and migration, and intracellular protein trafficking | (23,24) |
| GSK3A | Glycogen synthase kinase 3α | Control of several regulatory proteins including glycogen synthase and transcription factors | (25) |
| BAD | BCL2-associated agonist of cell death | Regulator of programmed cell death; proapoptotic activity of this protein is regulated through its phosphorylation; AKT and mitogen-activated protein kinase are involved in the regulation of this protein | (26,27) |
| AKTIP | AKT interacting protein | Mediates insulin-induced translocation of glucose transporter-4 to the cell surface | (28) |
| GSK3B | Glycogen synthase kinase 3β | Involved in energy metabolism, neuronal cell development and body pattern formation | (29) |
| ARP1 | Actin-related protein 1 | Transcriptional regulator involved in basal and hormone-regulated activity of prolactin; regulates the cell-specific trafficking of a receptor protein involved in apoptosis | (30,31) |
| PRR5 | Proline rich 5 (renal) | Regulates platelet-derived growth factor receptor | (32) |
| FOX1 | Fox-1 homolog. Also known as: ataxin 2-binding protein 1 (A2BP1); or hexaribonucleotide-binding | Possesses RNA binding motif; associated with spinocerebellar ataxia due to its binding to ataxin-2; regulator of tissue-specific alternative splicing in mammals protein 1 (HRNBP1) | (33) |
| BCL2 | B-cell lymphoma 2 | Oncogene; blocks apoptosis | (34,35) |
| WFIKKN2 | WAP, follistatin/kazal, immunoglobulin, kunitz | Protease-inhibitor that contains distinct protease inhibitor domains and netrin domain containing 2 | (36) |
| CREBBP | CREB binding protein | Regulates embryonic development, growth control, and homeostasis by coupling chromatin remodeling to transcription factor recognition | (37) |
| Caspase-9 | Apoptosis-related cysteine peptidase | Plays a central role in the execution-phase of cell apoptosis | (38) |
| PTK2 | Protein tyrosine kinase 2. Also known as: focal adhesion kinase (FAK) | Focal adhesion-associated protein involved in cellular adhesion and spreading processes; when it is blocked, cancer cells become less metastatic due to decreased mobility | (38,39) |
| FAS | Cell surface death receptor. Also known as: apoptosis antigen 1 (APO-1 or APT) | Plays a central role in the physiological regulation of programmed cell death | (40) |
| CDKN1A | Cyclin-dependent kinase inhibitor 1A. Also known as: P21; CIP1; SDI1; WAF1; CAP20; CDKN1; MDA-6; or p21CIP1 | Inhibits the activity of cyclin-CDK2 or -CDK4 complexes, and thus functions as a regulator of cell cycle progression at G1 phase | (41) |
| PSTPIP2 | Proline-serine-threonine phosphatase-interacting protein 2 | Substrate for a number of important signaling proteins | (42) |
| XIAP | X-linked inhibitor of apoptosis. Also known as: IAP3 and BIRC | Inhibits apoptosis | (43) |