TAGLN2 polymerizes G-actin in a low ionic state but blocks Arp2/3-nucleated actin branching in physiological conditions

• DOI: 10.1038/s41598-018-23816-2
• Publication Date: 2018-03-29T02:22:11Z
• Authors: Hye-Ran Kim; Min-Sung Kwon; Sangmin Lee; YeVin Mun; Kyung-Sik Lee; Chang-Hyun Kim; Bo-Ra Na; Bit Na Rae Kim; Indre Piragyte; Hyun-Su Lee; Youngsoo Jun; Mi Sun Jin; Young-Min Hyun; Hyun Suk Jung; Ji Young Mun; Chang-Duk Jun
• Keywords: Lamellipodium; MDia1; Actin remodeling; Filopodia; Actin-binding protein; Formins

TAGLN is an actin-binding protein family that comprises three isoforms with theorized roles in smooth muscle differentiation, tumour development, lymphocyte activation, and brain chemistry. However, their fundamental characteristics regulation of the actin-based cytoskeleton are not fully understood. Here we show TAGLN2 (including TAGLN1 TAGLN3) extensively nucleates G-actin polymerization under low-salt conditions, where would be completely suppressed. The calponin homology domain loop essential to mechanically connect two adjacent G-actins, thereby mediating multimeric interactions. blocked Arp2/3 complex binding actin filaments physiological salt inhibiting branched nucleation. In HeLa T cells, enhanced filopodium-like membrane protrusion. Collectively, dual functional nature TAGLN2-G-actin inhibition-may account for mechanisms filopodia development at edge Arp2/3-rich lamellipodia various cell types.