Polar Protein Exocytosis: Lessons from Plant Pollen Tube



Exocytosis is a highly regulated outward secretion process which participates in multiple cellular events including membrane modeling, cell polarization, cell wall formation, and cell signaling. Pollen tube is regarded as an ideal model plant cell system to study the machinery and regulation of exocytosis. Vigorous exocytic vesicle fusion with the apical plasma membrane supports the rapid and polarized pollen tube growth. However, the molecular identities and regulations of these exocytic vesicles still remain largely unexplored. Recent discoveries of various exocytic markers and regulatory proteins of exocytic pathway have advanced this research field rapidly. Here, we review and summarize the recent development and progress of protein exocytic trafficking and regulation in pollen tube, with emphasize on the pertinent questions for future understanding the functional roles of exocytosis in cell polarization and polar cell wall formation.


Tip growth Polar exocytosis Cell polarity Cell wall trans-Golgi network Golgi-derived vesicle 



Clathrin coated pits


Exocyst-positive organelle


Fluorescence recovery after photobleaching


Golgi-derived secretory vesicles


High-pressure freezing and substitution


Pre-vacuolar compartment


Plasma membrane


Pectin methylesterase


Receptor-like kinase


GTPase termed Rho of plant


Secretory carrier membrane protein


Stochastic optical reconstruction microscopy


Transmission electron microscopy


trans-Golgi network


Unconventional protein secretion


Variable-angle epifluorescence microscopy



Faqiang Li (South China Agricultural University) is acknowledged for helpful discussions. This work was supported by grants from Natural Science Foundation of China (NSFC, 31570001) and Natural Science Foundation of Guangdong Province, China (2016A030313401), to H.W. This work was also supported by grants from the Research Grants Council of Hong Kong (CUHK466011, 465112, 466613, CUHK2/CRF/11G, C4011-14R, HKUST10/CRF/12R, and AoE/M-05/12), NSFC/RGC (N_CUHK406/12), NSFC (31470294), and Croucher-CAS Joint Lab and Shenzhen Peacock Project (KQTD201101) to L.J.


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© Springer International Publishing AG 2017

Authors and Affiliations

  1. 1.College of Life SciencesSouth China Agricultural UniversityGuangzhouChina
  2. 2.School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong Kong, ShatinHong KongChina
  3. 3.CUHK Shenzhen Research InstituteThe Chinese University of Hong KongShenzhenChina

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