An evolutionarily conserved leucine-rich repeat protein CLERC is a centrosomal protein required for spindle pole integrity.
The centrosome functions as the microtubule-organizing center (MTOC) and plays a vital role in organizing spindle poles during mitosis. The pair of centrioles, which are the core components of the centrosome, duplicate once per cell cycle, and this feature is essential for the establishment of spindle bipolarity. Here we describe the molecular characterization of a novel protein called CLERC (Centrosomal leucine-rich repeat and coiled-coil containing protein) which is a human ortholog of Chlamydomonas Vfl1 protein. CLERC is a protein of 1032 amino acids with a calculated molecular mass of 120 kDa and possesses leucine-rich repeat and coiled-coil domains. Database searches revealed that CLERC has homologs in a wide variety of eukaryotes and is evolutionarily conserved. Endogenous CLERC protein associated with the centrosomes throughout the cell cycle and accumulated during mitosis. RNAi-mediated depletion of CLERC blocked formation of normal mitotic spindles and led to multipolar spindles. Moreover, many of the spindle poles in CLERC depleted cells contained only one centriole, indicating that centrosomes split into fractions containing a single centriole. These data indicate that the major function of CLERC during mitosis is to maintain the structural integrity of centrosomes, thereby contributing to spindle bipolarity.
Muto
Yoshinori
Y
Department of Functional Bioscience, Gifu University School of Medicine, Gifu, Japan. ymuto@gifu-u.ac.jp
Yoshioka
Takashi
T
Kimura
Masashi
M
Matsunami
Miki
M
Saya
Hideyuki
H
Okano
Yukio
Y
D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D002502:Centrioles / Q000378:metabolism; D018385:Centrosome / Q000378:metabolism*; D002696:Chlamydomonas / Q000737:chemistry; D017124:Conserved Sequence; D019143:Evolution, Molecular; D006801:Humans; D000090263:Leucine-Rich Repeat Proteins; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D008969:Molecular Sequence Data; D021381:Protein Transport; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
D018797:Cell Cycle Proteins; C532395:LRRCC1 protein, human; D000090263:Leucine-Rich Repeat Proteins; D011506:Proteins; D034741:RNA, Small Interfering