Cell-matrix adhesion controls Golgi organization and function through Arf1 activation in anchorage-dependent cells

Abstract

Cell-matrix adhesion regulates membrane trafficking controlling anchorage-dependent signaling. While a dynamic Golgi complex can contribute to this pathway, its regulation by adhesion remains unclear. Here we report that loss of adhesion dramatically disorganized the Golgi in mouse and human fibroblast cells. Golgi integrity is restored rapidly upon integrin-mediated re-adhesion to FN and is disrupted by integrin blocking antibody. In suspended cells, the cis, cis-medial and trans-Golgi networks differentially disorganize along the microtubule network but show no overlap with the ER, making this disorganization distinct from known Golgi fragmentation. This pathway is regulated by an adhesion-dependent reduction and recovery of Arf1 activation. Constitutively active Arf1 disrupts this regulation and prevents Golgi disorganization due to loss of adhesion. Adhesion-dependent Arf1 activation regulates its binding to the microtubule minus-end motor protein dynein to control Golgi reorganization, which is blocked by ciliobrevin. Adhesion-dependent Golgi organization controls its function, regulating cell surface glycosylation due to loss of adhesion, which is blocked by constitutively active Arf1. This study, hence, identified integrin-dependent cell-matrix adhesion to be a novel regulator of Arf1 activation, controlling Golgi organization and function in anchorage-dependent cells.

Mutant p53 induces Golgi tubulo-vesiculation driving a prometastatic secretome

“…In addition, we observed that miR-30d promotes secretion also by inducing microtubule stability, possibly via indirect effects on kinesins involved in dynamic assembly of Golgi mini-stacks 62,63 .…”

Genome-wide CRISPR screening identifies new regulators of glycoprotein secretion

“…Further studies will be required to fully understand how each gene regulates protein secretion. Interestingly, a recent study has shown the importance of the extracellular matrix (ECM) in regulating Golgi organisation and function via the activation of ARF1 27 . MXRA7, a component of the ECM, might play a similar role.…”

Endomembranes: Unsung Heroes of Mechanobiology?

“…Cell spreading upon adhesion triggers exocytosis of Golgi-derived vesicles delivering lipids required to expand the cell area (Gauthier et al, 2011). Cells in suspension display a fragmented Golgi already few minutes after losing contact with their substrate, a phenomenon that can be rescued by restoring Arf1 activity, which normally occurs downstream of activated integrins (Singh et al, 2018). Integrins are the main adhesion receptors of cells, and this observation suggests that the Golgi responds to a mechanotransduced signal downstream of integrins (Singh et al, 2018).…”

“…Cells in suspension display a fragmented Golgi already few minutes after losing contact with their substrate, a phenomenon that can be rescued by restoring Arf1 activity, which normally occurs downstream of activated integrins (Singh et al, 2018). Integrins are the main adhesion receptors of cells, and this observation suggests that the Golgi responds to a mechanotransduced signal downstream of integrins (Singh et al, 2018). Intriguingly, Golgi fragmentation in suspended cells was correlated with an increase in glycosylated proteins at the PM which did not depend on newly synthesized proteins, but rather on increased trafficking from the Golgi or increased Golgi-glycosylation activity (Singh et al, 2018).…”

“…Integrins are the main adhesion receptors of cells, and this observation suggests that the Golgi responds to a mechanotransduced signal downstream of integrins (Singh et al, 2018). Intriguingly, Golgi fragmentation in suspended cells was correlated with an increase in glycosylated proteins at the PM which did not depend on newly synthesized proteins, but rather on increased trafficking from the Golgi or increased Golgi-glycosylation activity (Singh et al, 2018). Hence, signaling originated from cellular adhesion could also affect the glycosylation function of the Golgi, but experimental evidence will be needed to confirm this speculation.…”