Arabidopsis  SABRE and CLASP interact to stabilize cell division plane orientation and planar polarity.
The orientation of cell division and the coordination of cell polarity within the plane of the tissue layer (planar polarity) contribute to shape diverse multicellular organisms. The root of Arabidopsis thaliana displays regularly oriented cell divisions, cell elongation and planar polarity providing a plant model system to study these processes. Here we report that the SABRE protein, which shares similarity with proteins of unknown function throughout eukaryotes, has important roles in orienting cell division and planar polarity. SABRE localizes at the plasma membrane, endomembranes, mitotic spindle and cell plate. SABRE stabilizes the orientation of CLASP-labelled preprophase band microtubules predicting the cell division plane, and of cortical microtubules driving cell elongation. During planar polarity establishment, sabre is epistatic to clasp at directing polar membrane domains of Rho-of-plant GTPases. Our findings mechanistically link SABRE to CLASP-dependent microtubule organization, shedding new light on the function of SABRE-related proteins in eukaryotes.
Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE-90 187 Umeå, Sweden.
Stefano
S
Pietra
Anna
A
Gustavsson
Christian
C
Kiefer
Lothar
L
Kalmbach
Per
P
Hörstedt
Yoshihisa
Y
Ikeda
Anna N
AN
Stepanova
Jose M
JM
Alonso
Markus
M
Grebe
D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002455:Cell Division / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology; D032461:Chromosomes, Plant; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny
D029681:Arabidopsis Proteins; C527272:CLASP protein, Arabidopsis; C579713:HPS4 protein, Arabidopsis; D047908:Intracellular Signaling Peptides and Proteins; D008869:Microtubule-Associated Proteins