Physical and functional interaction of K_V10.1 with Rabaptin‐5 impacts ion channel trafficking

Abstract

a b s t r a c t K V 10.1 is a potassium channel expressed in brain and implicated in tumor progression. We have searched for proteins interacting with K V 10.1 and identified Rabaptin-5, an effector of the Rab5 GTPase. Both proteins co-localize on large early endosomes induced by Rab5 hyperactivity. Silencing of Rabaptin-5 induces down-regulation of recycling of K V 10.1 channel in transfected cells and reduction of K V 10.1 current density in cells natively expressing K V 10.1, indicating a role of Rabaptin-5 in channel trafficking. K V 10.1 co-localizes, but does not physically interact, with Rab7 and Rab11. Our data highlights the complex control of the amount of K V 10.1 channels on the cell surface. Structured summary of protein interactions:Rabaptin-5 physically interacts with Kv10.1 by anti bait coimmunoprecipitation (View interaction) Rabaptin-5 physically interacts with Rabaptin-5 by two hybrid (View interaction) Kv10.1 physically interacts with Kv10.1 by two hybrid (View interaction) Kv10.1 physically interacts with Rabaptin-5 by anti bait coimmunoprecipitation (View Interaction: 1, 2) RAB11 and Kv10.1 colocalize by fluorescence microscopy (View interaction) Kv10.1 and Rabaptin-5 colocalize by fluorescence microscopy (View interaction) Kv10.1 physically interacts with Rabaptin-5 by two hybrid (View Interaction: 1, 2) Kv10.1 and RAB7 colocalize by fluorescence microscopy (View interaction)

PIST (GOPC) modulates the oncogenic voltage-gated potassium channel KV10.1

“…The C-terminus of K V 10.1 in fusion to the DNA binding domain of LexA transcription factor was used as a bait to screen a rat brain cDNA library fused to the activation domain of VP16 transcription factor. As previously reported (Ninkovic et al, 2012), out of 2 million screened clones, eight were positive for the HIS3 marker. One of them encoded most of the open reading frame of the murine PIST, including its PDZ domain (Neudauer et al, 2001).…”

“…Trafficking of K V 10.1 is not yet completely understood. We have recently described Rabaptin 5 (RABEP1) as an interaction partner of K V 10.1, linking this ion channel to early endosomes (Ninkovic et al, 2012). As an early event in the maturation and function of early endosomes Rabaptin 5 is able to bind and stabilize the GTP form Rab5, which then recruits effector proteins (Stenmark et al, 1995; Lippe et al, 2001).…”

“…Although there is evidence pointing to an additional non-canonical, permeation-independent role of the channel in cancer initiation and growth (Downie et al, 2008; Chen et al, 2011), inhibition of channel function exclusively at the plasma membrane by a monoclonal antibody (Gomez-Varela et al, 2007) reduces tumor progression in vivo , indicating that the membrane population of the channel is very important for its oncogenic properties. However, the mechanisms regulating the expression of K V 10.1 at the surface are still unclear, although it is known that the membrane residence time of the channel is relatively short, because it is internalized at a rate of 2% per minute (Kohl et al, 2011), and that both rabaptin 5 and cortactin are important to determine the abundance of K V 10.1 at the plasma membrane at a given time(Herrmann et al, 2012; Ninkovic et al, 2012). …”

High CO2 Leads to Na,K-ATPase Endocytosis via c-Jun Amino-Terminal Kinase-Induced LMO7b Phosphorylation

“…AP2-␤ mediates the formation of endocytic clathrin-coated vesicles from the plasma membrane by binding to clathrin (39)(40)(41). Other hypercapnia-induced LMO7b-interacting proteins include proteins that are involved in vesicular trafficking and/or membrane fusion, like cytoplasmic dynein 1 heavy chain 1 (42), Rab GTPase-binding effector protein 1 (43), cofilin 1 (44-46), septins (47,48), and Huntingtin-interacting protein 1 related (Hip1R) (49). Ezrin is involved in, among other functions, cytoskeletal anchoring at the plasma membrane (50).…”

El canal de potasio dependiente de voltaje Kv10.1 y el cáncer

“…Sánchez, et al lograron demostrar que la sobreexpresión del Kv10.1 inhibía la ciliogénesis, y que la reducción de su nivel de expresión mediante el uso de ARN de silenciamiento o interferencia, prolongaba la presencia del cilio primario (Sánchez, et al, 2016). Por lo tanto, el Kv10.1 promueve la endocitosis del cilio primario y explica por qué en anteriores investigaciones se demostró que el Kv10.1 interactuaba con proteínas involucradas en la endocitosis, como la cortactina (Herrmann, et al, 2012) y rabaptina 5 (Ninkovic, et al, 2012).…”