Two independent activities define Ccm1p as a moonlighting protein in Saccharomyces cerevisiae

Author:

Moreno J. Ignacio1,Patlolla Babu1,Belton Kerry R.1,Jenkins Brenita C.1,Radchenkova Polina V.1,Piva Marta A.1

Affiliation:

1. Department of Biological Sciences, Alcorn State University, 1000 ASU Drive 870, Alcorn State, MS 39096-7500, U.S.A.

Abstract

Ccm1p is a nuclear-encoded PPR (pentatricopeptide repeat) protein that localizes into mitochondria of Saccharomyces cerevisiae. It was first defined as an essential factor to remove the bI4 [COB (cytochrome b) fourth intron)] and aI4 [COX1 (cytochrome c oxidase subunit 1) fourth intron] of pre-mRNAs, along with bI4 maturase, a protein encoded by part of bI4 and preceding exons that removes the intronic RNA sequence that codes for it. Later on, Ccm1p was described as key to maintain the steady-state levels of the mitoribosome small subunit RNA (15S rRNA). bI4 maturase is produced inside the mitochondria and therefore its activity depends on the functionality of mitochondrial translation. This report addresses the dilemma of whether Ccm1p supports bI4 maturase activity by keeping steady-state levels of 15S rRNA or separately and directly supports bI4 maturase activity per se. Experiments involving loss of Ccm1p, SMDC (sudden mitochondrial deprivation of Ccm1p) and mutations in one of the PPR (pentatricopeptide repeat) motifs revealed that the failure of bI4 maturase activity in CCM1 deletion mutants was not due to a malfunction of the translational machinery. Both functions were found to be independent, defining Ccm1p as a moonlighting protein. bI4 maturase activity was significantly more dependent on Ccm1p levels than the maintenance of 15S rRNA. The novel strategy of SMDC described here allowed the study of immediate short-term effects, before the mutant phenotype was definitively established. This approach can be also applied for further studies on 15S rRNA stability and mitoribosome assembly.

Publisher

Portland Press Ltd.

Subject

Cell Biology,Molecular Biology,Biochemistry,Biophysics

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3