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Sahgal, P.

Publications and source records attributed to Sahgal, P..

2 recordsLinked to original sources

GGA2 and RAB13 regulate activity-dependent β1-integrin recycling

{beta}1-integrins mediate cell-matrix interactions and their trafficking is important in the dynamic regulation of cell adhesion, migration and malignant processes like cancer cell invasion. Here we employ an RNAi screen to characterize regulators of integrin traffic and identify the association of Golgi-localized gamma ear-containing Arf-binding protein 2 (GGA2) with {beta}1-integrin and its role in recycling of the active but not inactive {beta}1-integrin receptors. Silencing of GGA2 limits active {beta}1-integrin levels in focal adhesions and decreases cancer cell migration and invasion congruent with its ability to regulate the dynamics of active integrins. Using the proximity-dependent biotin identification (BioID) method, we identify two RAB family small GTPases, RAB13 and RAB10, associating with GGA2 and {beta}1-integrin. Functionally, RAB13 silencing triggers the intracellular accumulation of active {beta}1-integrin, reduces integrin activity, in focal adhesions, and cell migration, similarly to GGA2 depletion, indicating that both facilitate active {beta}1-integrin recycling the plasma membrane. Thus, GGA2 and RAB13 are important specificity determinants for integrin activity-dependent traffic.

cell biology

SORLA-driven endosomal trafficking regulates the oncogenic fitness of HER2

Human epidermal growth factor receptor 2 (HER2) is an oncogene targeted by several kinase inhibitors and therapeutic antibodies. Endosomal trafficking of many other receptor tyrosine kinases regulates their oncogenic signaling, but the prevailing view is that HER2 is retained on the cell surface. Here we reveal that in cancer cells Sortilin related receptor 1 (SORLA; SORL1) forms a complex with HER2 and regulates its subcellular distribution by promoting recycling of endosomal HER2 back to plasma membrane. Expression of SORLA in cancer cell lines and bladder cancers correlates with HER2 levels. Depletion of SORLA targets HER2 to late endosomal/lysosomal compartments, impairs HER2-driven signaling and in vivo tumor growth. SORLA silencing also disrupts normal lysosome function and sensitizes anti-HER2 therapy sensitive and resistant cancer cells to lysosome-targeting cationic amphiphilic drugs. These findings reveal potentially important SORLA-dependent endosomal trafficking-linked vulnerabilities in HER2-driven cancers.

cell biology