Pretty much any pathway database would allow you to do at least one of the two. Assuming that you are talking about a human protein involved in signal transduction, here are a few of the more relevant pathway databases to try:
There are lots of Pathway database tool but my preference goes to Reactome. From website you can do Pathway broswer, Pathway Analysis, Species comparison and Expression Analysis of eithe protein and encoded genes.
They have cross-reference wth NCBI Entrez Gene, Ensembl and UniProt databases, the UCSC and HapMap Genome Browsers, the KEGG Compound and ChEBI small molecule databases, PubMed, and Gene Ontology.
The rationale behind Reactome is to convey the rich information in the visual representations of biological pathways familiar from textbooks and articles in a detailed, computationally accessible format.
Netpath might be of interest
But I'd say KEGG is your best start - it can be linked to from the entrezgene page for your gene
R, treating pathway annotations with a pinch of salt since 2006
This could be a bacterial protein - in which case EcoCyc is a good choice. Could be a plant protein and so one may need a specialized pathway database for plants, eg here. The other responses are good - I'm just offering other sources of info.