AXL receptor tyrosine kinase regulates Golgi organization and function via an adhesion-Arf1 signalling axis in breast and lung cancer cell lines

Abstract

Cell-matrix adhesion regulates membrane trafficking, Golgi organization, and function. Altered Golgi organization in cancer cells may influence trafficking and cargo processing. A simple screen revealed distinct, adhesion-dependent differences in Golgi organization across breast (MDAMB231 versus MCF7) and lung (A549 versus CaLu1) cancer cell lines. To identify regulators driving these differences, we performed an in silico analysis of differentially expressed genes in the Cancer Cell Line Encyclopedia dataset, integrating Golgi-associated functions from interaction networks and literature. This analysis highlighted AXL as a putative Golgi regulator. AXL is prominently localized to the Golgi and is displaced upon inhibition with R428, which disrupts Golgi organization. AXL knockdown also does the same. AXL-mediated regulation of the Golgi is adhesion dependent. Mechanistically, AXL controls Arf1 activation through an AMPK-GBF1 pathway. Targeting of AMPK activation thus significantly reverses R428-mediated Golgi disorganization. Loss of adhesion promotes AMPK and reduces Arf1 activity, displacing AXL and Arf1 from the Golgi, driving its disorganization. This impacts Golgi-associated functions, tubulin acetylation in MDAMB231 cells, and cell-surface glycosylation in A549 cells. Together, our findings identify an adhesion-AXL-AMPK-GBF1-Arf1 pathway governing Golgi organization and function in cancer cells.