title: Kinectin-mediated endoplasmic reticulum dynamics supports focal adhesion growth in the cellular lamella.
abstract: Focal adhesions (FAs) control cell shape and motility, which are important processes that underlie a wide range of physiological functions. FA dynamics is regulated by cytoskeleton, motor proteins and small GTPases. Kinectin is an integral endoplasmic reticulum (ER) membrane protein that extends the ER along microtubules. Here, we investigated the influence of the ER on FA dynamics within the cellular lamella by disrupting the kinectin-kinesin interaction by overexpressing the minimal kinectin-kinesin interaction domain on kinectin in cells. This perturbation resulted in a morphological change to a rounded cell shape and reduced cell spreading and migration. Immunofluorescence and live-cell imaging demonstrated a kinectin-dependent ER extension into the cellular lamella and ER colocalisation with FAs within the cellular lamella. FRAP experiments showed that ER contact with FAs was accompanied with an increase in FA protein recruitment to FAs. Disruption of the kinectin-kinesin interaction caused a reduction in FA protein recruitment to FAs. This suggests that the ER supports FA growth within the cellular lamella. Microtubule targeting to FAs is known to promote adhesion disassembly; however, ER contact increased FA size even in the presence of microtubules. Our results suggest a scenario whereby kinectin-kinesin interaction facilitates ER transport along microtubules to support FA growth.
authors.affiliation: Graduate Program in Bioengineering, NUS Graduate School for Integrative Sciences and Engineering, 28 Medical Drive, 117456, Singapore.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Yee Han
authors.initials: YH
authors.lastname: Tee
authors.forename: Justin K
authors.initials: JK
authors.lastname: Heng
authors.forename: Yajuan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Xian
authors.initials: X
authors.lastname: Hu
authors.forename: Felix
authors.initials: F
authors.lastname: Margadant
authors.forename: Christoph
authors.initials: C
authors.lastname: Ballestrem
authors.forename: Alexander
authors.initials: A
authors.lastname: Bershadsky
authors.forename: Gareth
authors.initials: G
authors.lastname: Griffiths
authors.forename: Hanry
authors.initials: H
authors.lastname: Yu
mesh_terms: D002465:Cell Movement / Q000502:physiology; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D022001:Focal Adhesions / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D039661:Integrin beta3 / Q000378:metabolism; D016547:Kinesins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism
chemical_list: D039661:Integrin beta3; C088547:KTN1 protein, human; D008565:Membrane Proteins; D016547:Kinesins