Transmembrane kit ligand cleavage does not require a signal in the cytoplasmic domain and occurs at a site dependent on spacing from the membrane

Hwai-Jong Cheng, John G. Flanagan

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

The kit ligand (KL) is one of several growth factors that are active as transmembrane molecules and can also be proteolytically cleaved to yield soluble forms. We have investigated the signals and structural determinants that control the cleavage of KL. Presentation at the membrane appears to be critical, because no cleavage occurs in variants that lack a transmembrane domain. Signals in the cytoplasmic domain do not seem to be required, because cleavage was not blocked by removal of the C-terminal valine residue, deletion of the whole cytoplasmic tail, or the replacement of the cytoplasmic tail that occurs in the Sl(17H) mutation. KL thus appears to differ from transforming growth factor-α, which apparently requires a C-terminal valine as a signal for cleavage. Although proteolysis must be tightly restricted to the correct cell surface proteins and sites within each protein, cleavage of KL does not seem to be determined entirely by a requirement for a specific substrate sequence. However, the effects of deletion or insertion variants of KL suggest that cleavage may be limited to sites within a specific range of distances from the cell membrane.

Original languageEnglish (US)
Pages (from-to)943-953
Number of pages11
JournalMolecular Biology of the Cell
Volume5
Issue number9
StatePublished - Sep 1994
Externally publishedYes

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ASJC Scopus subject areas

  • Cell Biology
  • Genetics
  • Molecular Biology

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