INSR

INSR Full Name

insulin receptor

INSR Introduction

The insulin receptor (INSR) is a transmembrane tyrosine kinase receptor that plays a central role in maintaining metabolic homeostasis and cellular growth. It is primarily activated by insulin, a hormone responsible for regulating glucose uptake, energy storage, and anabolic metabolism. Structurally, INSR exists as a heterotetramer composed of two extracellular α-subunits that bind insulin and two transmembrane β-subunits that contain intrinsic tyrosine kinase activity. Upon insulin binding, the receptor undergoes autophosphorylation and triggers downstream signaling cascades that coordinate glucose transport, lipid metabolism, and protein synthesis. For researchers and clinicians studying metabolic disorders or growth signaling pathways, understanding INSR biology is essential because dysfunction of this receptor directly disrupts systemic glucose balance and cellular metabolic regulation.

Functionally, INSR mediates a range of intracellular signaling networks, most notably the PI3K/AKT and MAPK/ERK pathways. Activation of the PI3K/AKT axis promotes glucose transporter (GLUT4) translocation, glycogen synthesis, and cell survival, while the MAPK pathway contributes to cell proliferation and differentiation. These signaling events highlight why insulin receptor activity extends beyond metabolism and influences cell growth and tissue development. Emerging research has demonstrated that insulin and INSR can cooperate to drive oncogenic signaling in certain malignancies. For example, studies have shown that insulin signaling through INSR enhances proliferation, migration, and invasion of gastric cancer cells by activating PI3K/AKT and MAPK/ERK pathways. In addition, INSR expression can be transcriptionally regulated by tumor suppressor proteins such as p53, which directly binds to the INSR promoter and modulates its gene expression. Mutant forms of p53 may alter this regulatory mechanism, potentially contributing to abnormal insulin receptor signaling in cancers such as breast cancer.

Abnormal INSR signaling has been implicated in a wide spectrum of diseases, including metabolic disorders and cancer. In metabolic diseases such as type 2 diabetes, impaired insulin receptor signaling leads to insulin resistance, a condition in which cells fail to respond effectively to insulin stimulation. Beyond metabolic disorders, INSR has increasingly been recognized as a contributor to tumor progression. Elevated expression of INSR has been observed in pancreatic cancer tissues and is associated with poor clinical prognosis, suggesting that hyperactive insulin signaling may promote tumor growth and drug resistance. Additionally, the presence of insulin receptor isoforms, particularly the IR-A variant, allows cancer cells to respond not only to insulin but also to IGF-II, thereby amplifying mitogenic signaling. This complexity also presents therapeutic challenges: targeting IGF1R alone may not sufficiently block growth signals because INSR can function as an alternative pathway or form hybrid receptors with IGF1R. Consequently, many researchers now focus on strategies that simultaneously inhibit both insulin and IGF receptor signaling or selectively target tumor-associated receptor isoforms. These insights position INSR as an important molecular target in studies of metabolic disease, cancer biology, and the development of next-generation targeted therapies.

Alternate Names for INSR

INSR; insulin receptor; HHF5; CD220; IR; INSRA; INSR alpha; insulin receptor alpha

• 1.Saisana M, et al.; Insulin and the insulin receptor collaborate to promote human gastric cancer. Oncogene. 2021, 40(44):6330-6344.
  2.Heckl SM, et al.; Insulin Receptor in Pancreatic Cancer—Crown Witness in Cross Examination. Cancers (Basel). 2021, 13(19):4988.
  3.Cao J, Yee D. Disrupting Insulin and IGF Receptor Function in Cancer. Int J Mol Sci. 2021, 22(5):555.