The Fragile Fiber1 Kinesin Contributes to Cortical Microtubule-Mediated Trafficking of Cell Wall Components

Journal Article · Mon Feb 02 00:00:00 EST 2015 · Plant Physiology (Bethesda)

DOI:https://doi.org/10.1104/pp.114.251462· OSTI ID:2483313

Zhu, Chuanmei ^[1]; Ganguly, Anindya ^[1]; Baskin, Tobias I. ^[2]; McClosky, Daniel D. ^[3]; Anderson, Charles T. ^[3]; Foster, Cliff ^[4]; Meunier, Kristoffer A. ^[4]; Okamoto, Ruth ^[1]; Berg, Howard ^[5]; Dixit, Ram ^[1]

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1. Washington University, St. Louis, MO (United States)
2. University of Massachusetts, Amherst, MA (United States)
3. Pennsylvania State University, University Park, PA (United States)
4. Great Lakes Bioenergy Research Center, East Lansing, MI (United States)
5. Donald Danforth Plant Science Center, St. Louis, MO (United States)

The cell wall consists of cellulose microfibrils embedded within a matrix of hemicellulose and pectin. Cellulose microfibrils are synthesized at the plasma membrane, whereas matrix polysaccharides are synthesized in the Golgi apparatus and secreted. Here, the trafficking of vesicles containing cell wall components is thought to depend on actin-myosin. Here, we implicate microtubules in this process through studies of the kinesin-4 family member, Fragile Fiber1 (FRA1). In an fra1-5 knockout mutant, the expansion rate of the inflorescence stem is halved compared with the wild type along with the thickness of both primary and secondary cell walls. Nevertheless, cell walls in fra1-5 have an essentially unaltered composition and ultrastructure. A functional triple green fluorescent protein-tagged FRA1 fusion protein moves processively along cortical microtubules, and its abundance and motile density correlate with growth rate. Motility of FRA1 and cellulose synthase complexes is independent, indicating that FRA1 is not directly involved in cellulose biosynthesis; however, the secretion rate of fucose-alkyne-labeled pectin is greatly decreased in fra1-5, and the mutant has Golgi bodies with fewer cisternae and enlarged vesicles. Based on our results, we propose that FRA1 contributes to cell wall production by transporting Golgi-derived vesicles along cortical microtubules for secretion.

• Research Organization: University of Massachusetts, Amherst, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)
• Grant/Contract Number: FG02-03ER15421
• OSTI ID: 2483313
• Alternate ID(s): OSTI ID: 1210360
• Journal Information: Plant Physiology (Bethesda), Journal Name: Plant Physiology (Bethesda) Journal Issue: 3 Vol. 167; ISSN 0032-0889
• Publisher: American Society of Plant Biologists
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES