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Identification and characterization of Cor413im proteins as novel components of the chloroplast inner envelope
Author(s) -
OKAWA KUMIKO,
NAKAYAMA KATSUHIRO,
KAKIZAKI TOMOHIRO,
YAMASHITA TETSURO,
INABA TAKEHITO
Publication year - 2008
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2008.01854.x
Subject(s) - chloroplast membrane , inner membrane , arabidopsis , chloroplast , biology , chloroplast dna , plastid , membrane protein , microbiology and biotechnology , membrane , arabidopsis thaliana , envelope (radar) , mutant , biochemistry , gene , thylakoid , telecommunications , radar , computer science
Plastids are surrounded by two membrane layers, the outer and inner envelope membranes, which have various transport and metabolic activities. A number of envelope membrane proteins have been identified by biochemical approaches and have been assigned to specific functions. Despite those efforts, the chloroplast envelope membrane is expected to contain a number of as yet unidentified proteins that may affect specific aspects of plant growth and development. In this report, we identify and characterize a novel class of inner envelope membrane proteins, designated as Cor413 chloroplast inner envelope membrane group (Cor413im). Both in vivo and in vitro studies indicate that Cor413im proteins are targeted to the chloroplast envelope. Biochemical analyses of Cor413im1 demonstrate that it is an integral membrane protein in the inner envelope of chloroplasts. Quantitative real‐time PCR analysis reveals that COR413IM1 is more abundant than COR413IM2 in cold‐acclimated Arabidopsis leaves. The analyses of T‐DNA insertion mutants indicate that a single copy of COR413IM genes is sufficient to provide normal freezing tolerance to Arabidopsis . Based on these data, we propose that Cor413im proteins are novel components that are targeted to the chloroplast inner envelope in response to low temperature.