Fischer R S, Quinlan R A, Fowler V M
Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
FEBS Lett. 2003 Jul 17;547(1-3):228-32. doi: 10.1016/s0014-5793(03)00711-7.
Tropomodulin (Tmod) is an actin filament pointed end capping protein found in the membrane skeleton of lens fiber cells. We demonstrate that Tmod4 is able to bind the lens-specific intermediate filament protein, filensin, in either co-sedimentation or solid phase binding assays in a saturable fashion, but with low affinity and stoichiometry. Furthermore, Tmod4 does not bind the 53 kDa rod domain of filensin, nor to CP49, the obligate assembly partner of filensin. Finally, the binding of filensin to Tmod4 does not inhibit the actin capping activity of Tmod4 in vitro, suggesting that the two functions are not mutually exclusive.
原肌球蛋白（Tmod）是一种在晶状体纤维细胞膜骨架中发现的肌动蛋白丝尖端封端蛋白。我们证明，在共沉降或固相结合试验中，Tmod4能够以饱和方式结合晶状体特异性中间丝蛋白丝连蛋白，但亲和力和化学计量比很低。此外，Tmod4不结合丝连蛋白的53 kDa杆状结构域，也不结合丝连蛋白的专一组装伴侣CP49。最后，丝连蛋白与Tmod4的结合在体外并不抑制Tmod4的肌动蛋白封端活性，这表明这两种功能并非相互排斥。
