Contribution of the LIM domain and nebulin-repeats to the interaction of Lasp-2 with actin filaments and focal adhesions.
Lasp-2 binds to actin filaments and concentrates in the actin bundles of filopodia and lamellipodia in neural cells and focal adhesions in fibroblastic cells. Lasp-2 has three structural regions: a LIM domain, a nebulin-repeat region, and an SH3 domain; however, the region(s) responsible for its interactions with actin filaments and focal adhesions are still unclear. In this study, we revealed that the N-terminal fragment from the LIM domain to the first nebulin-repeat module (LIM-n1) retained actin-binding activity and showed a similar subcellular localization to full-length lasp-2 in neural cells. The LIM domain fragment did not interact with actin filaments or localize to actin filament bundles. In contrast, LIM-n1 showed a clear subcellular localization to filopodial actin bundles. Although truncation of the LIM domain caused the loss of F-actin binding activity and the accumulation of filopodial actin bundles, these truncated fragments localized to focal adhesions. These results suggest that lasp-2 interactions with actin filaments are mediated through the cooperation of the LIM domain and the first nebulin-repeat module in vitro and in vivo. Actin filament binding activity may be a major contributor to the subcellular localization of lasp-2 to filopodia but is not crucial for lasp-2 recruitment to focal adhesions.
Nakagawa
Hiroyuki
H
Division of Biology, Faculty of Science, Fukuoka University, Fukuoka, Japan. hnakagawa@fukuoka-u.ac.jp
Suzuki
Hiroshi
H
Machida
Satoshi
S
Suzuki
Junko
J
Ohashi
Kazuyo
K
Jin
Mingyue
M
Miyamoto
Shigeaki
S
Terasaki
Asako G
AG
D000199:Actins / Q000737:chemistry*; D000818:Animals; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D022001:Focal Adhesions / Q000737:chemistry*; D005982:Glutathione Transferase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000737:chemistry; D060588:LIM Domain Proteins; D051379:Mice; D008840:Microfilament Proteins / Q000737:chemistry*; D008856:Microscopy, Fluorescence / Q000379:methods; D008957:Models, Genetic; D009124:Muscle Proteins / Q000737:chemistry*; D009474:Neurons / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018909:src Homology Domains
D000199:Actins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D060588:LIM Domain Proteins; D008840:Microfilament Proteins; D009124:Muscle Proteins; C486890:NEBL protein, human; C035620:nebulin; D049452:Green Fluorescent Proteins; D005982:Glutathione Transferase