title: Kinectin-dependent ER transport supports the focal complex maturation required for chemotaxis in shallow gradients.
abstract: Chemotaxis in shallow gradients of chemoattractants is accomplished by preferential maintenance of protrusions oriented towards the chemoattractant; however, the mechanism of preferential maintenance is not known. Here, we test the hypothesis that kinectin-dependent endoplasmic reticulum (ER) transport supports focal complex maturation to preferentially maintain correctly oriented protrusions. We knocked down kinectin expression in MDA-MB-231 cells using small interfering RNA and observed that kinectin contributes to the directional bias, but not the speed, of cell migration. Kymograph analysis revealed that the extension of protrusions oriented towards the chemoattractant was not affected by kinectin knockdown, but that their maintenance was. Immunofluorescence staining and live-cell imaging demonstrated that kinectin transports ER preferentially to protrusions oriented towards the chemoattractant. ER then promotes the maturation of focal complexes into focal adhesions to maintain these protrusions for chemotaxis. Our results show that kinectin-dependent ER distribution can be localized by chemoattractants and provide a mechanism for biased protrusion choices during chemotaxis in shallow gradients of chemoattractants.
authors.affiliation: NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
authors.forename: Inn Chuan
authors.initials: IC
authors.lastname: Ng
authors.affiliation: NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
authors.forename: Pornteera
authors.initials: P
authors.lastname: Pawijit
authors.affiliation: Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
authors.forename: Lee Ying
authors.initials: LY
authors.lastname: Teo
authors.affiliation: Singapore-MIT Alliance, E4-04-10, 4 Engineering Drive 3, Singapore 117576, Singapore.
authors.forename: Huipeng
authors.initials: H
authors.lastname: Li
authors.affiliation: Confocal Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, Singapore.
authors.forename: Shu Ying
authors.initials: SY
authors.lastname: Lee
authors.affiliation: NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore, Singapore 117456, Singapore Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore Singapore-MIT Alliance, E4-04-10, 4 Engineering Drive 3, Singapore 117576, Singapore Confocal Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, Singapore Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore Institute of Bioengineering and Nanotechnology, A*STAR, Singapore 138669, Singapore Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, #10-01 CREATE Tower, Singapore 138602, Singapore Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA phsyuh@nus.edu.sg.
authors.forename: Hanry
authors.identifier: 0000-0002-0339-3685
authors.initials: H
authors.lastname: Yu
mesh_terms: D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics*; D002630:Chemotactic Factors / Q000235:genetics / Q000378:metabolism; D002633:Chemotaxis / Q000235:genetics*; D004721:Endoplasmic Reticulum / Q000235:genetics* / Q000378:metabolism; D022001:Focal Adhesions / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006801:Humans; D007734:Kymography; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D002630:Chemotactic Factors; C088547:KTN1 protein, human; D008565:Membrane Proteins
keywords: Chemotaxis; Endoplasmic reticulum; Focal complex maturation; Kinectin