Clark Kristopher, Middelbeek Jeroen, Dorovkov Maxim V, Figdor Carl G, Ryazanov Alexey G, Lasonder Edwin, van Leeuwen Frank N
Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
FEBS Lett. 2008 Sep 3;582(20):2993-7. doi: 10.1016/j.febslet.2008.07.043. Epub 2008 Aug 7.
TRPM6 and TRPM7 encode channel-kinases. While these channels share electrophysiological properties and cellular functions, TRPM6 and TRPM7 are non-redundant genes raising the possibility that the kinases have distinct substrates. Here, we demonstrate that TRPM6 and TRPM7 phosphorylate the assembly domain of myosin IIA, IIB and IIC on identical residues. Whereas phosphorylation of myosin IIA is restricted to the coiled-coil domain, TRPM6 and TRPM7 also phosphorylate the non-helical tails of myosin IIB and IIC. TRPM7 does not phosphorylate eukaryotic elongation factor-2 (eEF-2) and myosin II is a poor substrate for eEF-2 kinase. In conclusion, TRPM6 and TRPM7 share exogenous substrates among themselves but not with functionally distant alpha-kinases.
瞬时受体电位阳离子通道亚家族M成员6（TRPM6）和瞬时受体电位阳离子通道亚家族M成员7（TRPM7）编码通道激酶。虽然这些通道具有共同的电生理特性和细胞功能，但TRPM6和TRPM7是非冗余基因，这增加了激酶具有不同底物的可能性。在此，我们证明TRPM6和TRPM7在相同残基上磷酸化肌球蛋白IIA、IIB和IIC的组装结构域。虽然肌球蛋白IIA的磷酸化仅限于卷曲螺旋结构域，但TRPM6和TRPM7也磷酸化肌球蛋白IIB和IIC的非螺旋尾部。TRPM7不磷酸化真核生物延伸因子2（eEF-2），并且肌球蛋白II是eEF-2激酶的不良底物。总之，TRPM6和TRPM7彼此之间共享外源性底物，但不与功能上不相关的α激酶共享。
