The Role of Ubiquitination and Hepatocyte Growth Factor-Regulated Tyrosine Kinase Substrate in the Degradation of the Adrenomedullin Type I Receptor

Sci Rep. 2017 Sep 28;7(1):12389. doi: 10.1038/s41598-017-12585-z.

Abstract

Calcitonin receptor-like receptor (CLR) and the receptor activity-modifying protein 2 (RAMP2) comprise a receptor for adrenomedullin (AM). Although it is known that AM induces internalization of CLR•RAMP2, little is known about the molecular mechanisms that regulate the trafficking of CLR•RAMP2. Using HEK and HMEC-1 cells, we observed that AM-induced activation of CLR•RAMP2 promoted ubiquitination of CLR. A mutant (CLRΔ9KR), lacking all intracellular lysine residues was functional and trafficked similar to the wild-type receptor, but was not ubiquitinated. Degradation of CLR•RAMP2 and CLRΔ9KR•RAMP2 was not dependent on the duration of AM stimulation or ubiquitination and occurred via a mechanism that was partially prevented by peptidase inhibitors. Degradation of CLR•RAMP2 was sensitive to overexpression of hepatocyte growth factor-regulated tyrosine kinase substrate (HRS), but not to HRS knockdown, whereas CLRΔ9KR•RAMP2 degradation was unaffected. Overexpression, but not knockdown of HRS, promoted hyperubiquitination of CLR under basal conditions. Thus, we propose a role for ubiquitin and HRS in the regulation of AM-induced degradation of CLR•RAMP2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenomedullin / metabolism*
  • Calcitonin Receptor-Like Protein / genetics
  • Calcitonin Receptor-Like Protein / metabolism
  • Endosomal Sorting Complexes Required for Transport / genetics
  • Endosomal Sorting Complexes Required for Transport / metabolism*
  • Gene Knockdown Techniques
  • HEK293 Cells
  • Humans
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Protein Transport
  • Proteolysis
  • RNA, Small Interfering / metabolism
  • Receptor Activity-Modifying Protein 2 / genetics
  • Receptor Activity-Modifying Protein 2 / metabolism
  • Receptors, Adrenomedullin / metabolism*
  • Ubiquitin / metabolism
  • Ubiquitination / physiology*

Substances

  • Calcitonin Receptor-Like Protein
  • Calcrl protein, rat
  • Endosomal Sorting Complexes Required for Transport
  • Phosphoproteins
  • RNA, Small Interfering
  • Ramp2 protein, rat
  • Receptor Activity-Modifying Protein 2
  • Receptors, Adrenomedullin
  • Ubiquitin
  • hepatocyte growth factor-regulated tyrosine kinase substrate
  • Adrenomedullin