Messana Irene, Cabras Tiziana, Pisano Elisabetta, Sanna Maria Teresa, Olianas Alessandra, Manconi Barbara, Pellegrini Mariagiuseppina, Paludetti Gaetano, Scarano Emanuele, Fiorita Antonella, Agostino Stefania, Contucci Alessia M, Calò Lea, Picciotti Pasqualina M, Manni Armando, Bennick Anders, Vitali Alberto, Fanali Chiara, Inzitari Rosanna, Castagnola Massimo
Dipartimento di Scienze Applicate ai Biosistemi, Università di Cagliari, I-09042 Cagliari, Italy.
Mol Cell Proteomics. 2008 May;7(5):911-26. doi: 10.1074/mcp.M700501-MCP200. Epub 2008 Jan 9.
To elucidate the localization of post-translational modifications of different classes of human salivary proteins and peptides (acidic and basic proline-rich proteins (PRPs), Histatins, Statherin, P-B peptide, and "S type" Cystatins) a comparative reversed phase HPLC-ESI-MS analysis on intact proteins of enriched granule preparations from parotid and submandibular glands as well as parotid, submandibular/sublingual (Sm/Sl), and whole saliva was performed. The main results of this study indicate the following. (i) Phosphorylation of all salivary peptides, sulfation of Histatin 1, proteolytic cleavages of acidic and precursor basic PRPs occur before granule storage. (ii) In agreement with previous studies, basic PRPs are secreted by the parotid gland only, whereas all isoforms of acidic PRPs (aPRPs) are secreted by both parotid and Sm/Sl glands. (iii) Phosphorylation levels of aPRPs, Histatin 1, and Statherin are higher in the parotid gland, whereas the extent of cleavage of aPRP is higher in Sm/Sl glands. (iv) O-Sulfation of tyrosines of Histatin 1 is a post-translational modification specific for the submandibular gland. (v) The concentration of Histatin 3, Histatin 5, and Histatin 6, but not Histatin 1, is higher in parotid saliva. (vi) Histatin 3 is submitted to the first proteolytic cleavage (generating Histatins 6 and 5) during granule maturation, and it occurs to the same relative extent in both glands. (vii) The proteolytic cleavages of Histatin 5 and 6, generating a cascade of Histatin 3 fragments, take place after granule secretion and are more extensive in parotid secretion. (viii) Basic PRPs are cleaved in the oral cavity by unknown peptidases, generating various small proline-rich peptides. (ix) C-terminal removal from Statherin is more extensive in parotid saliva. (x) P-B peptide is secreted by both glands, and its relative quantity is higher in submandibular/sublingual secretion. (xi) In agreement with previous studies, S type Cystatins are mainly the product of Sm/Sl glands.
为阐明不同种类人类唾液蛋白质和肽（富含酸性和碱性脯氨酸的蛋白质（PRPs）、组蛋白、磷蛋白、P-B肽和“S型”胱抑素）翻译后修饰的定位，对腮腺和颌下腺以及腮腺、颌下/舌下腺（Sm/Sl）和全唾液中富集颗粒制剂的完整蛋白质进行了比较反相高效液相色谱-电喷雾电离质谱分析。本研究的主要结果如下：（i）所有唾液肽的磷酸化、组蛋白1的硫酸化、酸性和前体碱性PRPs的蛋白水解切割在颗粒储存之前发生。（ii）与先前研究一致，碱性PRPs仅由腮腺分泌，而酸性PRPs（aPRPs）的所有同工型由腮腺和Sm/Sl腺分泌。（iii）腮腺中aPRPs、组蛋白1和磷蛋白的磷酸化水平较高，而Sm/Sl腺中aPRP的切割程度较高。（iv）组蛋白1酪氨酸的O-硫酸化是颌下腺特有的翻译后修饰。（v）腮腺唾液中组蛋白3、组蛋白5和组蛋白6的浓度较高，但组蛋白1并非如此。（vi）组蛋白3在颗粒成熟过程中经历首次蛋白水解切割（产生组蛋白6和5），且在两个腺体中发生的相对程度相同。（vii）组蛋白5和6的蛋白水解切割产生一系列组蛋白3片段，在颗粒分泌后发生，且在腮腺分泌中更广泛。（viii）碱性PRPs在口腔中被未知肽酶切割，产生各种富含脯氨酸的小肽。（ix）腮腺唾液中磷蛋白C末端的去除更广泛。（x）P-B肽由两个腺体分泌，其相对含量在颌下/舌下分泌中较高。（xi）与先前研究一致，S型胱抑素主要是Sm/Sl腺的产物。
