Immunohistological localization ofsmgp25A, arasp21-like guanosine 5′-triphosphate (GTP)-binding protein in human skin
✍ Scribed by S. Inohara; Y. Tanaka; Y. Kitano; S. Sagami; A. Mizoguchi; A. Kikuchi; Y. Takai
- Publisher
- Springer-Verlag
- Year
- 1992
- Tongue
- English
- Weight
- 548 KB
- Volume
- 284
- Category
- Article
- ISSN
- 0340-3696
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✦ Synopsis
In addition to a group of guanosine 5'-triphosphate (GTP)-binding proteins (G proteins) having an e/~7 subunit structure and serving as transducers for membrane receptors, there is another group of ras p21-1ike G proteins in mammalian tissue without a subunit structure whose molecular value is about 20 000 [1,10]. This group of ras p21-1ike G proteins is designated as small G proteins [1,10]. Bovine brain membranes were the source from which smg p25A was first purified and its cDNA has been isolated [3,4]. This small G proteins shows both GTP/guanosine 5'-diphosphate (GDP) binding and GTPase activities as described for other small G proteins [3].
Although the function of smg p25A has not been defined, it is likely that it is involved in secretory processes of mammalin secretory cells. This assertion is based on the observation that smg p25A is found only in secretory cells, such as synapses of brain, and endocrine and exocrine secretory cells [5], and that it shows the highest amino acid sequence homology with the yeast SEC4 and YPT1 proteins which have been shown to be involved in yeast secretory processes [7,9]. In the study reported here, we examined immunohistochemically the tissue distribution of smg p25A in human skin, in order to elucidate its participation in skin including secretory cells of apocrine and eccrine glands.
Anti-smg p25A monoclonal antibody was prepared by a routine method [5,6]. Non-immune mouse IgG was purchased from Amersham, UK, and fluorescein-labelled goat anit-mouse IgG was purchased from TAGO, USA. Human axillar skin was obtained surgically from individuals aged from 18 to 23 years with osmidrosis axillae. The specimens were immediately snap-frozen in liquid nitrogen, and stored at -70 ~ unti used. Serial 5-gin sections were cut on a cryostat at -20 ~ air-dried, and