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PTRN ‐1/ CAMSAP promotes CYK ‐1/formin‐dependent actin polymerization during endocytic recycling
Author(s) -
Gong Ting,
Yan Yanling,
Zhang Jing,
Liu Shuai,
Liu Hang,
Gao Jinghu,
Zhou Xin,
Chen Juan,
Shi Anbing
Publication year - 2018
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.15252/embj.201798556
Subject(s) - formins , biology , microbiology and biotechnology , actin , endocytic cycle , polymerization , cytoskeleton , actin cytoskeleton , biochemistry , endocytosis , chemistry , cell , polymer , organic chemistry
Cargo sorting and membrane carrier initiation in recycling endosomes require appropriately coordinated actin dynamics. However, the mechanism underlying the regulation of actin organization during recycling transport remains elusive. Here we report that the loss of PTRN ‐1/ CAMSAP stalled actin exchange and diminished the cytosolic actin structures. Furthermore, we found that PTRN ‐1 is required for the recycling of clathrin‐independent cargo hTAC ‐ GFP . The N‐terminal calponin homology ( CH ) domain and central coiled‐coils ( CC ) region of PTRN ‐1 can synergistically sustain the flow of hTAC ‐ GFP . We identified CYK ‐1/formin as a binding partner of PTRN ‐1. The N‐terminal GTP ase‐binding domain ( GBD ) of CYK ‐1 serves as the binding interface for the PTRN ‐1 CH domain. The presence of the PTRN ‐1 CH domain promoted CYK ‐1‐mediated actin polymerization, which suggests that the PTRN ‐1‐ CH : CYK ‐1‐ GBD interaction efficiently relieves autoinhibitory interactions within CYK ‐1. As expected, the overexpression of the CYK ‐1 formin homology domain 2 ( FH 2) substantially restored actin structures and partially suppressed the hTAC ‐ GFP overaccumulation phenotype in ptrn‐1 mutants. We conclude that the PTRN ‐1 CH domain is required to stimulate CYK ‐1 to facilitate actin dynamics during endocytic recycling.