Rock B M, Xin L, Wilcox J N
Department of Dermatology, Emory University, Atlanta, Georgia 30322, USA.
J Invest Dermatol. 1997 Nov;109(5):645-9. doi: 10.1111/1523-1747.ep12337646.
G proteins link many cell surface receptor generated signals to activation of multiple cellular processes in all tissues. There is specificity in the receptor interaction with the G protein and in the interaction of the specific G protein with different effector molecules. The purpose of this study was to determine some of the biologically relevant G proteins in keratinocytes. The G alpha subunit of the heterotrimeric G protein was investigated because much of the biologic activity and the receptor specificity resides there. A polymerase chain reaction strategy was used that amplified multiple G alpha gene segments between conserved primer sites from keratinocyte first strand cDNA. Two Gq class G proteins, G alpha 16 and G alpha y, were identified. Using northern analysis and in situ hybridization, mRNA of both of these genes were detected in keratinocytes in culture and in epidermal keratinocytes. G alpha y was expressed in multiple other cell types and tissues, but G alpha 16 was restricted in expression to keratinocytes and keratinocyte-derived adnexal structures in the skin. G alpha 16 has previously been reported to be limited in expression to hematopoietic cells. The physiologic receptor to which it couples in neutrophils is reported to be a C5a receptor. The receptor to which it couples in keratinocytes has not been elucidated but by analogy may be another chemokine receptor. We hypothesize that G alpha 16 is an important conduit for responses to inflammatory signals in keratinocytes.
G蛋白将许多细胞表面受体产生的信号与所有组织中多种细胞过程的激活联系起来。受体与G蛋白的相互作用以及特定G蛋白与不同效应分子的相互作用具有特异性。本研究的目的是确定角质形成细胞中一些具有生物学相关性的G蛋白。研究了异源三聚体G蛋白的Gα亚基，因为其大部分生物活性和受体特异性都存在于此。采用聚合酶链反应策略，从角质形成细胞第一链cDNA的保守引物位点之间扩增多个Gα基因片段。鉴定出两种Gq类G蛋白，Gα16和Gαy。通过Northern分析和原位杂交，在培养的角质形成细胞和表皮角质形成细胞中检测到这两种基因的mRNA。Gαy在多种其他细胞类型和组织中表达，但Gα16的表达仅限于皮肤中的角质形成细胞和角质形成细胞衍生的附属结构。此前报道Gα16的表达仅限于造血细胞。据报道，它在中性粒细胞中偶联的生理受体是C5a受体。它在角质形成细胞中偶联的受体尚未阐明，但类推可能是另一种趋化因子受体。我们假设Gα16是角质形成细胞对炎症信号作出反应的重要途径。
