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ER/Golgi trafficking is facilitated by unbranched actin filaments containing Tpm4.2
Author(s) -
Kee Anthony J.,
Bryce Nicole S.,
Yang Lingyan,
Polishchuk Elena,
Schevzov Galina,
Weigert Roberto,
Polishchuk Roman,
Gunning Peter W.,
Hardeman Edna C.
Publication year - 2017
Publication title -
cytoskeleton
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 86
eISSN - 1949-3592
pISSN - 1949-3584
DOI - 10.1002/cm.21405
Subject(s) - biology , golgi apparatus , actin , microbiology and biotechnology , biophysics , endoplasmic reticulum
We have identified novel actin filaments defined by tropomyosin Tpm4.2 at the ER. EM analysis of mouse embryo fibroblasts (MEFs) isolated from mice expressing a mutant Tpm4.2 ( Tpm4 Plt53/Plt53 ), incapable of incorporating into actin filaments, revealed swollen ER structures compared with wild‐type (WT) MEFs ( Tpm4 +/+ ). ER‐to‐Golgi, but not Golgi‐to‐ER trafficking was altered in the Tpm4 Plt53/Plt53 MEFs following the transfection of the temperature sensitive ER‐associated ts045 ‐VSVg construct. Exogenous Tpm4.2 was able to rescue the ER‐to‐Golgi trafficking defect in the Tpm4 Plt53/Plt53 cells. The treatment of WT MEFs with the myosin II inhibitor, blebbistatin, blocked the Tpm4.2‐dependent ER‐to‐Golgi trafficking. The lack of an effect on ER‐to‐Golgi trafficking following treatment of MEFs with CK666 indicates that branched Arp2/3‐containing actin filaments are not involved in anterograde vesicle trafficking. We propose that unbranched, Tpm4.2‐containing filaments have an important role in maintaining ER/Golgi structure and that these structures, in conjunction with myosin II motors, mediate ER‐to‐Golgi trafficking.