In vivo role of focal adhesion kinase in regulating pancreatic β-cell mass and function through insulin signaling, actin dynamics, and granule trafficking

EP Cai, M Casimir, SA Schroer, CT Luk, SY Shi… - Diabetes, 2012 - Am Diabetes Assoc
EP Cai, M Casimir, SA Schroer, CT Luk, SY Shi, D Choi, XQ Dai, C Hajmrle, AF Spigelman…
Diabetes, 2012Am Diabetes Assoc
Focal adhesion kinase (FAK) acts as an adaptor at the focal contacts serving as a junction
between the extracellular matrix and actin cytoskeleton. Actin dynamics is known as a
determinant step in insulin secretion. Additionally, FAK has been shown to regulate insulin
signaling. To investigate the essential physiological role of FAK in pancreatic β-cells in vivo,
we generated a transgenic mouse model using rat insulin promoter (RIP)–driven Cre-loxP
recombination system to specifically delete FAK in pancreatic β-cells. These RIPcre+ fak fl/fl …
Focal adhesion kinase (FAK) acts as an adaptor at the focal contacts serving as a junction between the extracellular matrix and actin cytoskeleton. Actin dynamics is known as a determinant step in insulin secretion. Additionally, FAK has been shown to regulate insulin signaling. To investigate the essential physiological role of FAK in pancreatic β-cells in vivo, we generated a transgenic mouse model using rat insulin promoter (RIP)–driven Cre-loxP recombination system to specifically delete FAK in pancreatic β-cells. These RIPcre+fakfl/fl mice exhibited glucose intolerance without changes in insulin sensitivity. Reduced β-cell viability and proliferation resulting in decreased β-cell mass was observed in these mice, which was associated with attenuated insulin/Akt (also known as protein kinase B) and extracellular signal–related kinase 1/2 signaling and increased caspase 3 activation. FAK-deficient β-cells exhibited impaired insulin secretion with normal glucose sensing and preserved Ca2+ influx in response to glucose, but a reduced number of docked insulin granules and insulin exocytosis were found, which was associated with a decrease in focal proteins, paxillin and talin, and an impairment in actin depolymerization. This study is the first to show in vivo that FAK is critical for pancreatic β-cell viability and function through regulation in insulin signaling, actin dynamics, and granule trafficking.
Am Diabetes Assoc