Rab11 and Its Effector Rab Coupling Protein Contribute to the Trafficking of β1 Integrins during Axon Growth in Adult Dorsal Root Ganglion Neurons and PC12 Cells

Abstract

Integrins play an important part in axon growth, but integrin traffic in neurons is poorly understood. Expression of the tenascin-Cbinding integrin ␣9 promotes axon regeneration. We have therefore studied the mechanism by which ␣9 integrin and its partner ␤1 are trafficked along axons and at the growth cone using adult DRG neurons and PC12 cells. We have focused on the small GTPase Rab11 and its effector Rab coupling protein (RCP), as they are involved in the long-range trafficking of ␤1 integrins in other cells. Rab11 colocalizes with ␣9 and other ␣ integrins and with ␤1 integrin in growth cones and axons, and immunopurified Rab11 vesicles contain ␣9 and ␤1. Endocytosed ␤1 integrins traffic via Rab11. However, Rab11 vesicles in axons are generally static, and ␣9 integrins undergo bouts of movement during which they leave the Rab11 compartment. In growth cones, ␣9 and ␤1 overlap with RCP, particularly at the growth cone periphery. We show that ␤1 integrin trafficking during neurite outgrowth involves Rab11 and RCP, and that manipulation of these molecules alters surface integrin levels and axon growth, and can be used to enhance ␣9 integrin-dependent neurite outgrowth. Our data suggest that manipulation of trafficking via Rab11 and RCP could be a useful strategy for promoting integrin-dependent axonal regeneration.

Reggie-1/Flotillin-2 regulates integrin trafficking and focal adhesion turnover via Rab11a

“…The Rab11/ARF-6 dependent recycling of integrins was demonstrated by Eva and colleagues as an essential molecular mechanism for the regeneration of axons in mammals (Eva et al, 2010(Eva et al, , 2012. This is in line with our present results on the interaction of reggie and Rab11a at trafficking cargo vesicles during cell migration (Stuermer, 2010).…”

“…Moreover, RCP/Rab11-driven recycling of ␣5␤1-integrin controls the activation of Rac and RhoA in different cell lines (A2780, MDA-MB-231 and HT1080 cells) (Jacquemet et al, 2013). The recycling of ␤1-integrin is known to be regulated by Arf6 and Rab11 (Eva et al, 2010(Eva et al, , 2012Powelka et al, 2004) and Rab11 was also implied in the targeted delivery of Src tyrosine kinases to FAs (Bach et al, 2014) where Src contributes to the phosphorylation of FAK (Canel et al, 2013). In addition, ␤1-integrin recruitment can lead to an activation of Rac1 in HeLa cells (O'Toole et al, 2011).…”

Nerve Growth Factor and Nociception: From Experimental Embryology to New Analgesic Therapy

“…Interestingly, the STOML3 containing vesicles are not part of the signaling endosome pool as they are Rab5 negative, but are Rab11 positive. Rab11-positive vesicles have been characterized as composing a slowly recycling endocytic compartment and may be transported predominantly anterogradely in sensory neurons (Ascaño et al, 2009;Eva et al, 2010). Indeed gain or loss of function Rab11 mutants radically change vesicle behavior but these compartments still contain STOML3 (Lapatsina et al, 2012b).…”

Structure-Function Analyses of the Interactions between Rab11 and Rab14 Small GTPases with Their Shared Effector Rab Coupling Protein (RCP)

“…Overexpression of dominant-negative mutants of RCP and Rab11, or their knockdown, has been shown to inhibit neurite outgrowth in dorsal root ganglion neurons and PC12 cells (36). Neuritogenesis can be readily induced in N2a cells by withdrawing serum.…”