We have made the novel discovery that MARCKS protein (Myristoylated Alanine-Rich C Kinase Substrate) is a key molecule regulating mucin secretion from human bronchial epithelial ceils in vitro, and in mice in vivo. In this renewal, we propose to elucidate the precise molecular mechanisms whereby MARCKS controls the secretory process in airway epithelium, utilizing both in vitro and in vivo models. The hypothetical mechanism is a new paradigm for exocytotic release of preformed, membrane-bound secretory granules from airway epithelium. In this mechanism, membrane-bound secretory granules containing pre-formed mucin exist in the cell, associated with a number of specific fusion and docking proteins, as """"""""secretory modules."""""""" Each secretory module is fully equipped for fusion with the plasma membrane and resultant exocytotic release of the granule contents into the airway lumen. However, the module lacks the necessary apparatus to translocate to the plasmalemma. This is where MARCKS is critical: MARCKS, phosphorylated by PKC, moves to the cytoplasm, where it is brought to the secretory module by binding to the chaperone, heat shock protein 70 (Hsp 70). The Hsp 70/MARCKS complex binds to the secretory module via the N-terminus of MARCKS by interaction with a specific granule membrane protein, cysteine string protein (CSP). After its PKG-mediated dephosphorylation by protein phosphatase 2A (PP2A), MARCKS binds to actin/myosin while still attached to the secretory module. Thus, MARCKS links mucin granules to the contractile cytoskeleton. Upon translocation to the plasma membrane, fusion and docking proteins associated with the secretory module (Rab 3, VAMP 2 and VAMP 8) in conjunction with target proteins in the plasmlemma, position the granules for exocytosis. Critical aspects of this mechanism will be addressed utilizing 3 model systems: 1. primary human airway epithelial cells; 2. a human airway epithelial cell line (HBE1); and 3. an in vivo murine model of mucin hypersecretion.
The aims will define the mechanisms whereby MARCKS binds to Hsp70, how the MARCKS/Hsp70 complex binds to CSP on granule membranes, and specific fusion and docking proteins of the secretory module involved in exocytotic release of mucin both in vitro and in vivo.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Method to Extend Research in Time (MERIT) Award (R37)
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Special Emphasis Panel (ZRG1-ALTX-4 (02))
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Banks-Schlegel, Susan P
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North Carolina State University Raleigh
Anatomy/Cell Biology
Schools of Veterinary Medicine
United States
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Yin, Qi; Fang, Shijing; Park, Joungjoa et al. (2016) An Inhaled Inhibitor of Myristoylated Alanine-Rich C Kinase Substrate Reverses LPS-Induced Acute Lung Injury in Mice. Am J Respir Cell Mol Biol 55:617-622
Chen, Ching-Hsien; Cheng, Chun-Ting; Yuan, Yuan et al. (2015) Elevated MARCKS phosphorylation contributes to unresponsiveness of breast cancer to paclitaxel treatment. Oncotarget 6:15194-208
Chen, C-H; Thai, P; Yoneda, K et al. (2014) A peptide that inhibits function of Myristoylated Alanine-Rich C Kinase Substrate (MARCKS) reduces lung cancer metastasis. Oncogene 33:3696-706
Chen, Ching-Hsien; Chiu, Chun-Lung; Adler, Kenneth B et al. (2014) A novel predictor of cancer malignancy: up-regulation of myristoylated alanine-rich C kinase substrate phosphorylation in lung cancer. Am J Respir Crit Care Med 189:1002-4
Sheats, Mary K; Pescosolido, Kimberly C; Hefner, Ethan M et al. (2014) Myristoylated Alanine Rich C Kinase Substrate (MARCKS) is essential to ?2-integrin dependent responses of equine neutrophils. Vet Immunol Immunopathol 160:167-76
Chen, Ching-Hsien; Statt, Sarah; Chiu, Chun-Lung et al. (2014) Targeting myristoylated alanine-rich C kinase substrate phosphorylation site domain in lung cancer. Mechanisms and therapeutic implications. Am J Respir Crit Care Med 190:1127-38
Newcomb, Dawn C; Boswell, Madison G; Sherrill, Taylor P et al. (2013) IL-17A induces signal transducers and activators of transcription-6-independent airway mucous cell metaplasia. Am J Respir Cell Mol Biol 48:711-6
Li, Jingjing; D'Annibale-Tolhurst, Melissa A; Adler, Kenneth B et al. (2013) A myristoylated alanine-rich C kinase substrate-related peptide suppresses cytokine mRNA and protein expression in LPS-activated canine neutrophils. Am J Respir Cell Mol Biol 48:314-21
Fang, Shijing; Crews, Anne L; Chen, Wei et al. (2013) MARCKS and HSP70 interactions regulate mucin secretion by human airway epithelial cells in vitro. Am J Physiol Lung Cell Mol Physiol 304:L511-8
Green, Teresa D; Park, Joungjoa; Yin, Qi et al. (2012) Directed migration of mouse macrophages in vitro involves myristoylated alanine-rich C-kinase substrate (MARCKS) protein. J Leukoc Biol 92:633-9

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