The membrane proteins TRAMp and sec61αp may be involved in post‐translational transport of presecretory proteins into mammalian microsomes

FEBS Letters

Klappa, Peter¹  Zimmermann, Richard¹  Zimmermann, Maria¹ 

[1] Institut für Biochemie und Molekulare Zellbiologie der Universität Göttingen, Goßlerstr. 12d, D-37073 Göttingen, Germany

关键词: Mammalian microsome;    Post-translational protein transport;    Chemical cross-linking;   

DOI  :  10.1016/0014-5793(94)80473-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The presecretory protein ppcecDHFR, a hybrid between preprocecropinA and dihydrofolate reductase, is transported into mammalian microsomes post-translationally, i.e. independent of ribosome and signal recognition particle. Here, the involvement of microsomal proteins in ribonucleoparticle-independent transport of ppcecDHFR was analyzed by transport into trypsin-pretreated microsomes and by transport of a truncated version of ppcecDHFR and subsequent chemical cross-linking. We observed that post-translational transport of ppcecDHFR can occur into microsomes which had been pretreated with trypsin (final concentration, 100μg/ml) and that of the known transport components only TRAMp and sec61αp are still present under these conditions. Furthermore, we found that the truncated ppcecDHFR, ppcecDHFR-98mer′, can be cross-linked to 36 kDa microsomal membrane proteins during post-translational transport. Therefore, the two microsomal membrane proteins with molecular masses of about 36 kDa, TRAMp and secolαp, appear to be involved in the post-translational transport of ppcecDHFR and ppcecDHFR-98mer.

【 授权许可】

Unknown