The P124A mutation of SRP14 alters its migration on SDS-PAGE without impacting its function  

作　　者：Yaofu Liu Jinqiu Zhou 

机构地区：[1]Key Laboratory of Systems Health Science of Zhejiang Province,School of Life Science,Hangzhou Institute for Advanced Study,University of Chinese Academy of Sciences,Hangzhou 310024,China [2]Institute of Biochemistry and Cell Biology,Chinese Academy of Sciences,University of Chinese Academy of Sciences,Shanghai 200031,China

出　　处：《Acta Biochimica et Biophysica Sinica》2024年第2期315-322,共8页生物化学与生物物理学报（英文版）

基　　金：This work was supported by the grants from the National Key Research and Development Program of China(No.2019YFA0109902);the National Natural Science Foundation of China(No.32200419).

摘　　要：SRP14 is a crucial protein subunit of the signal recognition particle(SRP),a ribonucleoprotein complex essential for co-translational translocation to the endoplasmic reticulum.During our investigation of SRP14 expression across diverse cell lines,we observe variations in its migration on sodium dodecyl sulfate-polyacrylamide gel electro-phoresis(SDS-PAGE),with some cells exhibiting slower migration and others migrating faster.However,the cause of this phenomenon remains elusive.Our research rules out alternative splicing as the cause and,instead,iden-tifies the presence of a P124A mutation in SRP14(SRP14P124A)among the faster-migrating variants,while the slower-migrating variants lack this mutation.Subsequent ectopic expression of wild-type SRP14P124 or SRP14WT and SRP14P124A in various cell lines confirms that the P124A mutation indeed leads to faster migration of SRP14.Further mutagenesis analysis shows that the P117A and A121P mutations within the alanine-rich domain at the C-terminus of SRP14 are responsible for migration alterations on SDS-PAGE,whereas mutations outside this domain,such as P39A,Y27F,and T45A,have no such effect.Furthermore,the ectopic expression of SRP14WT and SRP14P124A yields similar outcomes in terms of SRP RNA stability,cell morphology,and cell growth,indicating that SRP14P124A represents a natural variant of SRP14 and retains comparable functionality.In conclusion,the substitution of proline for alanine in the alanine-rich tail of SRP14 results in faster migration on SDS-PAGE,but has little effect on its function.

关 键 词：SRP14 proline mutation point mutation alanine-rich domain MIGRATION 

分 类 号：Q52[生物学—生物化学]