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Biochemistry, Biophysics, and Structural Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

2011

University of Massachusetts - Amherst

Articles 1 - 3 of 3

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Rac/Rop Gtpases And Auxin Signaling, H. Wu, O. Hazak, Alice Cheung, S. Yalovsky Apr 2011

Rac/Rop Gtpases And Auxin Signaling, H. Wu, O. Hazak, Alice Cheung, S. Yalovsky

Alice Cheung

Auxin functions as a key morphogen in regulating plant growth and development. Studies on auxin-regulated gene expression and on the mechanism of polar auxin transport and its asymmetric distribution within tissues have provided the basis for realizing the molecular mechanisms underlying auxin function. In eukaryotes, members of the Ras and Rho subfamilies of the Ras superfamily of small GTPases function as molecular switches in many signaling cascades that regulate growth and development. Plants do not have Ras proteins, but they contain Rho-like small G proteins called RACs or ROPs that, like fungal and metazoan Rhos, are regulators of cell polarity ...


Pollen Tubes Lacking A Pair Of K+ Transporters Fail To Target Ovules In Arabidopsis, Y. Lu, S. Chanroj, L. Zulkifli, M. Johnson, N. Uozumi, Alice Cheung, H. Sze Jan 2011

Pollen Tubes Lacking A Pair Of K+ Transporters Fail To Target Ovules In Arabidopsis, Y. Lu, S. Chanroj, L. Zulkifli, M. Johnson, N. Uozumi, Alice Cheung, H. Sze

Alice Cheung

Flowering plant reproduction requires precise delivery of the sperm cells to the ovule by a pollen tube. Guidance signals from female cells are being identified; however, how pollen responds to those cues is largely unknown. Here, we show that two predicted cation/proton exchangers (CHX) in Arabidopsis thaliana, CHX21 and CHX23, are essential for pollen tube guidance. Male fertility was unchanged in single chx21 or chx23 mutants. However, fertility was impaired in chx21 chx23 double mutant pollen. Wild-type pistils pollinated with a limited number of single and double mutant pollen producing 62% fewer seeds than those pollinated with chx23 single ...


The Sv40 Late Protein Vp4 Is A Viroporin That Forms Pores To Disrupt Membranes For Viral Release, Smita Raghava, Kristen Giorda, F. Romano, Alejandro Heuck, Daniel Hebert Jan 2011

The Sv40 Late Protein Vp4 Is A Viroporin That Forms Pores To Disrupt Membranes For Viral Release, Smita Raghava, Kristen Giorda, F. Romano, Alejandro Heuck, Daniel Hebert

Alejandro P. Heuck

Nonenveloped viruses are generally released by the timely lysis of the host cell by a poorly understood process. For the nonenveloped virus SV40, virions assemble in the nucleus and then must be released from the host cell without being encapsulated by cellular membranes. This process appears to involve the well-controlled insertion of viral proteins into host cellular membranes rendering them permeable to large molecules. VP4 is a newly identified SV40 gene product that is expressed at late times during the viral life cycle that corresponds to the time of cell lysis. To investigate the role of this late expressed protein ...